C-terminal Motifs of HIV-1 gp41 as Possible Determinants of Viral Pathogenesis / Motivos C-terminales de gp41 del VIH-1 como posibles determinantes de la patogénesis viral / Motivos C-terminais do HIV-1 gp41 como Possíveis Determinantes da Patogénese Viral

Abstract: human immunodeficiency virus type 1 (HIV-1) is the etiological agent of acquired immunodeficiency syndrome (AIDS), a pandemic with high economic and social costs. The envelope glycoprotein (ENV) of the virus mediates the infectious process by binding to and entering the host cell, one of the main target components of studies since its discovery. Its endodomain or C-terminal tail (CTT) participates in late replicative cycle processes, such as intracellular trafficking, activation, and cell death, which occurs because it interacts with multiple cellular factors through motifs or signal sequences present throughout its structure. Although these interactions have not been fully understood at specific levels, studies over more than three decades leave no doubtthatthis domain plays a fundamental role in the biology of the virus and probably the development of the disease. This review describes the studies carried out to date that demonstrate the importance of the CTT, focusing on the motifs responsible for its interactions and its possible roles in the pathogenicity of the infection.

Resumen: el virus de la inmunodeficiencia humana tipo 1 (VIH-1) es el agente etiológico del síndrome de inmunodeficiencia adguirida (SIDA), una pandemia con altos costos económicos y sociales. La glicoproteína de la envoltura (ENV) del virus media el proceso infeccioso al unirse a la célula huésped y entrar en ella, uno de los principales componentes objetivo de los estudios desde su descubrimiento. Su endodominio o cola C-terminal (CTT) participa en procesos tardíos del ciclo replicativo, como tráfico intracelular, activación y muerte celular, lo que ocurre porque interactúa con múltiples factores celulares a través de motivos o secuencias señal presentes en toda su estructura. Aunque estas interacciones no se han entendido completamente a niveles específicos, los estudios durante más de tres décadas no dejan dudas de que este campo juega un papel fundamental en la biología del virus y probablemente en el desarrollo de la enfermedad. Esta revisión describe los estudios realizados hasta la fecha que demuestran la importancia de la CTT, centrándose en los motivos responsables de sus interacciones y sus posibles roles en la patogenicidad de la infección.

Resumo: o vírus da imunodeficiência humana tipo 1 (HIV-1) é o agente etiológico da síndrome da imunodeficiência adquirida (AUXILIA), urna pandemia com elevados custos económicos e sociais. A glicoproteína do envelope (ENV) do vírus media o processo infeccioso ligando-se e entrando na célula hospedeira, um dos principais componentes alvo dos estudos desde sua descoberta. Seu endo domínio ou cauda C-terminal (CTT) participa de processos do ciclo replicativo tardio, como tráfego intracelular, ativação e morte celular, que ocorre porque interage com múltiplos fatores celulares por meio de motivos ou sequências-sinal presentes em toda a sua estrutura. Embora essas interações não tenham sido totalmente compreendidas em níveis específicos, estudos ao longo de mais de três décadas não deixam dúvidas de que esse domínio desempenha um papel fundamental na biologia do vírus e provavelmente no desenvolvimento da doença. Esta revisão descreve os estudos realizados até o momento que demonstram a importância da CTT, com foco nos motivos responsáveis por suas interações e seus possíveis papéis na patogenicidade da infecção.

Small molecule HIV entry inhibitors targeting gp120 or gp41:research advances / 国际药学研究杂志

The envelope glycoprotein subunit gp120 and the transmembrane subunit gp41 of human immunodeficiency virus type 1(HIV-1)play important roles in the process of viral entry into target cells, and serve as key targets for developing HIV-1 entry inhibitors. Peptide HIV entry inhibitors, such as T20, are limited in clinical application due to the lack of oral properties. However, because of the possible oral administration and high bioavailability, small molecule compounds become more and more important in the research for HIV entry inhibitors. In this review, we summarize the recent advances in the development of small molecule HIV-1 entry inhibitors, including the NBD and BMS series of small-molecule inhibitors targeting gp120 as well as the NB-206 and ADS-J1 se- ries of small-molecule inhibitors targeting gp41. These small molecule inhibitors are promising compounds with research value, which lay a foundation for the design of more efficient and more reasonable small-molecule HIV-1 entry inhibitors.

The development of HIV vaccines targeting gp41 membrane-proximal external region (MPER): challenges and prospects

A human immunodeficiency virus type-1 (HIV-1) vaccine which is able to effectively prevent infection would be the most powerful method of extinguishing pandemic of the acquired immunodeficiency syndrome (AIDS). Yet, achieving such vaccine remains great challenges. The membrane-proximal external region (MPER) is a highly conserved region of the envelope glycoprotein (Env) gp41 subunit near the viral envelope surface, and it plays a key role in membrane fusion. It is also the target of some reported broadly neutralizing antibodies (bNAbs). Thus, MPER is deemed to be one of the most attractive vaccine targets. However, no one can induce these bNAbs by immunization with immunogens containing the MPER sequence(s). The few attempts at developing a vaccine have only resulted in the induction of neutralizing antibodies with quite low potency and limited breadth. Thus far, vaccine failure can be attributed to various characteristics of MPER, such as those involving structure and immunology; therefore, we will focus on these and review the recent progress in the field from the following perspectives: (1) MPER structure and its role in membrane fusion, (2) the epitopes and neutralization mechanisms of MPER-specific bNAbs, as well as the limitations in eliciting neutralizing antibodies, and (3) different strategies for MPER vaccine design and current harvests.

Characterization of Gp41 Polymorphisms in the Fusion Peptide Domain and T-20 (Enfuvirtide) Resistance-Associated Regions in Korean HIV-1 Isolates

HIV-1 gp41 is an envelope protein that plays an essential role in virus entry. The mutation of gp41 affects HIV-1 entry and susceptibility to the fusion inhibitor T-20. Therefore, we analyzed the natural polymorphism of gp41 of 163 HIV-1 isolates from T-20-naive Koreans infected with HIV-1. This study of gp41 polymorphisms showed that insertions in the fourth threonine (74.8%) and L7M substitutions (85.3%) were more frequent in the fusion peptide motif in Korean HIV-1 isolates compared with those from other countries. Minor T-20 resistance mutations such as L45M (1.2%), N126K (1.2%), and E137K (6.7%) were detected, but the critical T-20 resistance mutations were not detected in the gp41 HR1 and HR2 regions. In addition, the N42S mutation (12.9%) associated with T-20 hypersusceptibility was detected at a high frequency. These results may serve as useful data for studies considering T-20 for use in the development of a more effective anti-retroviral treatment in Korea.

Testing a subtyee-specific gp41 amplification mthod for genotyping individualss infected by human immunodeficiency virus type-1 in the Brazilian population of itajaí, south Brazil / Teste da metodologia de amplificação subtipo-específica da gp41 para genotipagem de indivíduos infectados pelo Vírus da Imunodeficiência Humana tipo 1 na população de Itajaí, Sul do Brasil

The method used by YAGYU et al. for the subtype-specific polymerase chain reaction (PCR) amplification of the gp41 transmembrane region of the human immunodeficiency virus type-1 (HIV-1) env gene, was tested. HIV-1 proviral DNA from 100 infected individuals in Itajaí, South Brazil was used to analyze this method. Seventy individuals were determined according to this method as having PCR products at the expected size for subtypes B, C, D and F. Of these individuals, 26 (37.1%) were observed as having the expected amplification for subtype C, and 42 (60%) were observed as having the expected products for subtypes B and D. Of the subtype B and D amplicons, 16 (22.9%) were classified as subtype D, and 26 (37.1%) were classified as subtype B. Two individuals (2.9%) had amplicons that were observed after subtype F-specific amplification was performed. Sequencing and comparing the patient sequences to reference sequences confirmed the classification of sequences of subtypes C and B. However, sequences that were falsely determined as being D and F in the PCR assay were determined as being subtypes C and B, respectively, by sequence analysis. For those individuals from whom no amplified products were obtained, a low viral load that was indicated in their patient history may explain the difficulty in subtyping by PCR methods. This issue was demonstrated by the results of ANOVA when testing the effect of viral load on the success of PCR amplification. The alignment of the obtained sequences with HIV-1 reference sequences demonstrated that there is high intra-subtype diversity. This indicates that the subtype-specific primer binding sites were not conserved or representative of the subtypes that are observed in the Brazilian populations, and that they did not allow the correct classification of HIV-1 subtypes. Therefore, the proposed method by YAGYU et al. is not applicable for the classification of Brazilian HIV-1 subtypes.

A metodologia para amplificação subtipo-específica por PCR da região transmembrana do gene env (gp41) do HIV-1, descrita por Yagyu e colaboradores, foi testada a partir de DNA proviral de 100 pacientes infectados pelo HIV-1 de Itajaí, Sul do Brasil. Setenta indivíduos apresentaram produtos amplificados e correspondentes aos subtipos B, C, D e F de acordo com a metodologia escolhida. Destes indivíduos, 26 (37,1%) apresentaram a amplificação esperada para o subtipo C de acordo com a metodologia; 42 (60%) apresentaram os produtos esperados para os subtipos B e D, sendo que na etapa seguinte de diferenciação destes subtipos, 16 (22,9%) corresponderam ao subtipo D e 26 (37,1%) ao subtipo B. Dois indivíduos (2,9%) mostraram produtos amplificados após a amplificação específica para o subtipo F. O sequenciamento e a comparação com sequências referências confirmou a subtipagem de HIV-1 C e B obtida pela metodologia. No entanto, indivíduos subtipados erroneamente como HIV-1 D e F pela metodologia, foram classificados pela comparação com sequências referências como subtipos C e B, respectivamente. Em relação aos indivíduos que não mostraram produtos amplificados, a baixa carga viral observada no histórico destes pacientes seria em parte responsável pela dificuldade na subtipagem pela metodologia de PCR, como demonstrado pelo resultado significativo no ANOVA ao testar o efeito da carga viral no sucesso da amplificação. O alinhamento das sequências obtidas com sequências referências de HIV-1 correspondentes à região da gp41 demonstrou que há uma alta diversidade intra-subtipo e que as regiões a partir das quais foram desenhados os oligonucleotídeos iniciadores HIV-1 subtipo-específicos não são conservadas nem suficientemente representativas dos subtipos observados nas populações brasileiras para permitir sua correta identificação. Portanto, esta metodologia não é aplicável para populações virais brasileiras.

The anti-HIV-1 entrance activity and mechanism of action of myriceric acid B from Rhoiptelea chiliantha Diels et Hand-Mazz / 中国药理学通报

Aim To investigate the HIV-1 entry inhibitory activities of myriceric acid B and C isolated from Rhoiptelea chiliantha Diels et Hand-Mazz and their mechanism of action.Method The plasmids encoding envelope proteins of HIV-1 (pHXB2) and VSV (pVSV-G) were cotransfected 293T cells with pNL4-3.Luc.R-E- to produce HIV-1 Env pseudovirus and VSV-G pseudovirus,respectively,which were used for testing the antiviral activities of these compounds.ELISA and molecular docking were used to study the mechanism of action of the active compounds.Results Myriceric acid B could significantly inhibit the infection of HIV-1 Env pseudovirus with an IC_(50) of(8.3±0.2)mg·L~(-1).The carbonoxyl group at C-28 position and the hydroxyl group at the C-3 position of myriceric acid B are important for its anti-HIV-1 activity.Like other HIV-1 entry inhibitors targeting gp41 (eg,ADS-J1 and NB-64), myriceric acid B could also block the gp41 six-helix bundle formation.Molecular docking analysis suggests that myriceric acid B may bind to the hydrophobic cavity of the gp41 N-trimeric coiled coil.Conclusion Myriceric acid B is a potent HIV-1 entry inhibitor targeting gp41 and can serve as a lead compound for developing novel anti-HIV-1 drug.

Acid native polyacrylamide gel electrophoresis:a method for studying the mechanism of action of HIV entry inhibitor ADS-J1 / 中国药理学通报

Aim ADS-J1 is a low molecular HIV entry inhibitor targeting HIV transmembrane subunit gp41 through virtual screening from a compound library containing 20 000 molecules.This study is to investigate the binding sites of ADS-J1 on gp41.Methods Acid native polyacrylamide gel electrophoresis (AN-PAGE) assay was applied to test the binding ability of ADS-J1 with the peptides derived from gp41 N-terminal heptad repeat (NHR) region.Results It was reported previously that ADS-J1 could block the gp41 six-helix bundle (6-HB) formation using native polyacrylamide gel electrophoresis (N-PAGE).However,the binding sites could not be found because positive charged N-peptides derived from gp41 NHR could not show bands on the gel.In the present study,the AN-PAGE assay which could show N-peptides in the gel was established,and it was found that ADS-J1 could inhibit the gp41 6-HB formation.Moreover,ADS-J1 bound directly to the gp41 cavity region of NHR.The positively charged residue (K574) located in this region was critical for the binding of ADS-J1.Conclusions ADS-J1 inhibits HIV entry by targeting the cavity region of gp41 NHR,whereas K574 in the cavity plays a critical role for the binding.Furthermore,the AN-PAGE assay provides a simple method for studying the mechanism of action of virus entry inhibitors targeting the transmembrane protein of type I enveloped virus.

Amino acid mutatios of gp41 2F5 and 4E10 neutralizing epitopes of 92 HIV-1 infected individuals and AIDS patients in China / 中华微生物学和免疫学杂志

Objective To study the amino acid mutations in neutralizing antibody 2F5 and 4E10 conserved epitopes ELDKWA and NWFDIT of HIV-1 membrane proximal external region(MPER)in 92 HIV-infected individuals and AIDS patients in China,and to provide a basis for the neutralizing antobodies immunotherapy and a design of vaccines. Methods Nest-PCR methods were used to amplity genes of the HIV-1 env gp41 region.The amplified fragments were sequenced by double-deoxygen terminal method and translated into amino acids for analysis.The mutations of 2F5 and 4E10 neutralizing epitopes were identified by comparison with the epitopes reference data in HIV-1 Sequence Database.Results There were mutations on both 2F5 and 4E10 neutralizing epitopes.2F5 conserved neutralizing epitopes major mutations tocused on E662A(14.1%),K665S(17.4%),A667K(16.3%),and 4E10 conserved neutralizing epltopes major mutations included N671S(13.0%),D674S(3.3%),T676S(16.3%).The mutation rates of 2F5 and 4E10 epitopes were significanfly different between CRF_B'C-clade and B'-clade(P<0.05).The mutata rates of CRF_B'C-clade were higher than that of CRFOI_AE-clade in 2F5 epitopes(P<0.05).The mutation rates of B'-clade in 4E10 eiptopes showed significant difference in slow progressors,HIV-infected individuals and AIDS patients,respectively(P<0.05).Conclusion The HIV-1 patients in China are demonstrated diversified mutations in 2F5 and 4E10 neutralizing epitopes.The mutation degrees of amlno acids in conserved neutralizing epitopes are different in different subtypes.There may be a correlation between neutralizing epitopes mutations of 4E10 with disease progression.

Prokaryotic Expression and Functional Study of HIV-1 Envelope Glycoprotein gp41 Helical Bundle / 中国生物工程杂志

HIV-1 envelope glycoprotein gp41,which is a hopeful target for HIV-1 fusion inhibitors,plays a critical role in the fusion of viral and cellular membranes.In order to build up the screening assay of HIV-1 fusion inhibitors targeting gp41,HIV-1 gp41 5-helix and 6-helix were expressed in prokaryotic cells.Gp41 5-helix and 6-helix recombined plasmids were constructed by using PCR,enzyme digestion and ligation taking the clade B HIV-1 genome as a template.The plasmid was transferred into E.coli BL21(DE3)and then induced by IPTG.The expressed protein was purified by affinity chromatography after denaturation and renaturation.The SDS-PAGE analysis was used during expression and purification.Native-PAGE was used to identify the interaction between gp41 5-helix and T-20.The result will be helpful to build up the screening assay of HIV-1 fusion inhibitors targeting gp41.

Spectrin Cleavage Induced by LLP-1 Lentivirus Lytic Peptide Domain in the Intracytoplasmic Tail of Human Immunodeficiency Virus Type 1 GP41 in Rat Organotypic Hippocampal Slice Cultures

We previously demonstrated that the lentivirus lytic peptide 1 (LLP-1) corresponding to the carboxyl terminus of HIV-1 gp41 induced cell death in human neuronal cells. Present study was conducted to further elucidate the pathogenic mechanisms involved in HIV-1 gp41-induced neurodegeneration in AIDS patients with cognitive deficits. The effect of LLP-1 on activation of calpain-1, a calcium-activated cysteine protease, which has been implicated in neuronal degeneration and death, was monitored by the proteolysis of spectrin in rat organotypic hippocampal slice cultures. Protease specific spectrin breakdown products revealed that LLP-1 generated~150/145-kDa fragments characteristic of calpain-1 activation in hippocampus undergoing cell death as evidenced by LDH release. This spectrin cleavage pattern was further confirmed by in vitro calpain-1 proteolysis. Futhermore, calpectin and MDL28170, inhibitors of calpain activity, blocked calpain-1-mediated spectrin cleavage. Spectrin cleavage likely occurred in the absence of overt synaptic loss, as suggested by the preserved levels of synaptophysin. Among pharmacological agents tested, apocynin, NADPH oxidase inhibitor, ameliorated the LLP-1-induced spectrin. Given the role of spectrin essential for synapse stabilization, LLP-1-induced spectrin cleavage as occurs with the activation of calpain-1 may be an important effector in LLP-1mediated cell injury in hippocampus, which is primarily linked to cognitive dysfunction.

Structure-activity relationships of anti-HIV-1 peptides with disulfide linkage between D- and L-cysteine at positions i and i+3, respectively, derived from HIV-1 gp41 C-peptide

The constrained alpha-helical structure of a C-peptide is useful for enhancing anti-HIV-1 activity. The i and i+3 positions in an alpha-helical structure are located close together, therefore D-Cys (dC) and L-Cys (C) were introduced at the positions, respectively, to make a dC-C disulfide bond in 28mer C-peptides. Accordingly, this study tested whether a dC-C disulfide bond would increase the alpha-helicity and anti-HIV-1 activity of peptides. A C-peptide can be divided into three domains, the N-terminal hydrophobic domain (HPD), middle interface domain (IFD), and C-terminal hydrogen domain (HGD), based on the binding property with an N-peptide. In general, the dC-C modifications in HPD enhanced the anti-HIV-1 activity, while those in IFD and HGD resulted in no or much less activity. The modified peptides with no activity clearly showed much less alpha-helicity than the native peptides, while those with higher activity showed an almost similar or slightly increased alpha-helicity. Therefore, the present results suggest that the introduction of a dC-C bridge in the N-terminal hydrophobic domain of a C-peptide may be useful for enhancing the anti-HIV-1 activity.

Advancement in developing a new class of anti-AIDS drugs: HIV entry inhibitors / 中国药理学通报

Process of HIV fusion with target cells, mediated by the HIV envelope glycoprotein surface subunit gp120 and the transmembrane subunit gp41, is an important step for drug intervention. The membrane fusion events leading to HIV entry into the target cell are initiated by the binding of gp120 to CD4 and subsequently to a co-receptor, CXCR4 or CCR5. Consequently, gp41 undergoes conformational changes, resulting in the fusion between the viral and cellular membranes or between the infected and uninfected cells. Therefore, gp120 and gp41 on the virions and CD4 and coreceptors on the target cells may serve as targets for development of a new class of anti-HIV drugs, HIV entry inhibitors, with a mechanism of action different from those mediated by reverse transcriptase inhibitors (RTIs) and protease inhibitors (PIs), the two classes of antiretroviral drugs approved by FDA for clinical application. The successful development of a peptidic anti-HIV drug T-20, which is targeted to the HIV gp41, implies that HIV entry inhibitors are milestone in the current anti-HIV therapy. Application of the HIV entry inhibitors alone or in combination with the RTIs and PIs will increase the efficacy and reduce the toxicity of these anti-HIV drugs and will save lives of AIDS patients who fail to response to the current antiretroviral drugs. The advancement in the study and development of the HIV entry inhibitors was reviewed here in detail

Peptidic HIV fusion inhibitors targeting envelope glycoprotein transmembrane subunit gp41 / 中国药理学通报

HIV envelope glycoprotein transmembrane subunit gp41 plays a major role in the fusion of viral and target cell membranes. The extracellular region of gp41 consists of N-terminal fusion peptide and downstream N- and C-heptad repeat (NHR and CHR) regions. The peptidesderived from the NHR and CHR regions, designated N- and C-peptides, respectively, have potent inhibitory activity on the HIV mediated cell fusion. C-peptide T-20 has just got the approval of U.S. FDA, which became the first success of one new class anti-HIV agents, named HIV-fusion inhibitors. However, a relatively long peptide such as T-20 suffers from several limitations including proteolytic sensitivity, large dosage, therefore it is unable to produced by gene engineering. Alternately, shorter peptidic fusion inhibitors and active peptides suitable for gene engineering are pursued. In the recent years, this kind of peptide modifications are hot spots in HIV research field and contribute a lot to the inhibitory mechanism of N- and C-peptide.

Research progress on the structure of HIV envelope glycoprotein and related HIV entry inhibitors / 中国药理学通报

HIV-1 envelope glycoprotein gp120 and gp41 are considered as two important parts in viral entry.In the process of virus entry,CD4 first binds to gp120 and causes the conformation of gp120 to change.Furthermore the conformation of gp41 has also been changed.Many peptides,macromolecular compounds and small molecule compounds which bind to gp120 or gp41 can deter the progress of virus entry.These compounds can play an important role in halting the spread of HIV-1 in this way.The structure and interaction of gp120 and gp41 are reviewed here,as well as the anti-HIV agents blocking the HIV entry by targeting the HIV-1 envelope glycoprotein.

Screening and identification of HIV-1 gp41 core structure epitope from random phage display peptide library / 中国免疫学杂志

Objective:To identify and characterize the epitopes on core structure of HIV 1 gp41.Methods:A random phage displayed dodecapeptide library was screened with a conformation specific monoclonal antibody NC 1 specifically against the core structure of HIV 1 gp41.The positive clones were identified by sandwich ELISA,soluble NC 1 blocking assay and competitive inhibition assay.Results:After three rounds of screening,10 of 24 phage clones were identified as positive clones which can bind to NC 1.Amino acid sequences deduced from DNA sequences showed five different sequences:HDVHHRWVYLLS?ITVNEWLYTSEQ?HGRSHGMFKPKR?MGPIARPHWHLN?DMYRSPRPKPDT.The binding between phage clones(displayed HDVHHRWVYLLS,VNEWLYTSEQ and MGPIARPHWHLN, respectively)and NC 1 could be inhibited by N36 C34 complex.Soluble NC 1 could block the binding between phage clones and NC 1.Conclusion:The results indicate that HDVHHRWVYLLS,VNEWLYTSEQ and MGPIARPHWHLN are the mimotopes which could mimic the core structrue epitopes of six helix bundle of HIV 1 gp41.

Construction,expression and purification of HIV-1 p24-gp41 fusion protein in E.coli / 中华传染病杂志

Objective To construct recombinant plasmid with p24 and gp41 gene, express fusion protein in E.coli. Methods To design primer with restriction endonuclease position,and amplify p24 and gp41 by RT-PCR, link both into pMD18-T vector.To choose correct clone with target gene.Then p24 fragment will be cleaved and linked into pMD18-T vector within gp41 gene. Both post-linked gene will be cleaved and linked into pET21a vector. The vector will be transformed into E.coli. And protein is highly effective expressed in E coli. Western blotting proved that the expressed product could react with 6?his antibody. Result Fusion protein p24-gp41 is highly effective expressed in E.coli. Conclusion Fusion protein p24-gp41 is highly effective expressed in E.coli in pET21a vector.

Screening and identification of HIV-1 gp41 C-helix mimotopes displayed on phages / 中国免疫学杂志

Objective:To find small molecular leads for inhibition on early stage of HIV infection by identification and characterization of the HIV-1 gp41 C-helix mimotopes.Methods:For identification of the gp41 C-helix mimotopes,C7C phage display peptide library was biopanning by using a synthetic peptide N36 which was derived from the gp41 N-helix as target.After three rounds of screening,positive phage clones were identified by ELISA and sequenced.Results:16 of 26 phage clones were identified to bind with peptide N36,and 10 of them were sequenced.Every clone of ten clones contains at least two hydrophobic residues,which may dock into the hydrophobic pocket in the gp41 N-helix domain.9 of the 10 clones have a conservative sequence WW,which may mimic the W628 and W631 in C-helix to interact with the hydrophobic residues in the gp41 pocket.One clone expressing the conservative sequence named clone No.8(CYWWHRLHC) was selected for characterization.The binding between the clone No.8 and N36 was blocked by free peptide N36.And the binding between clone No.8 and peptide N36 was inhibited by peptide C34(IC 50=12.5 ?g/ml).Conclusion:The short circular peptides displayed on phages containing WW residues may mimic the conformational epitope of the HIV-1 gp41 C-helix to interact with the N-helix.This information may be useful for design of HIV-1 fusion inhibitors.

Effect of HIV-1 Gp41 Peptide on Expression and Metabolism of Amyloid Precursor Protein in Human Astroglioma Cell

Significant neurodegeneration leading to neurocognitive disorder and dementia has been observed in the central nervous system (CNS) of patients with HIV infection. Part of the neurodegenerative cascade in AIDS dementia may involve glial cells, perhaps through inhibiting the release of glial factors that protect neurons from variety of insults. Here, in an effort to find the mediators of HIV-induced brain damage, we examined the possible effect of a HIV-1 transmenbrane protein gp41 peptide (583-599) on expression and metabolism of amyloid precursor protein (APP) using human astroglial cell line. RT-PCR analysis demonstrated that gp 41 peptide did not significantly change expression patterns of APP mRNAs in lipopolysaccharide (LPS) activated astroglial cells for 6h. In contrast, gp41 peptide remarkably downregulated the level of secreted from of APP (sAPPa), which has been recently demonstrated as a potent neuroprotective factor. The reverse peptide, used as control had no such effect. The mechanism of gp41 peptide-induced down regulation of sAPPa production appears to be TGF-beta independent. These results implicate that gp41 peptide could be one of the mediator involved in the modulation of APP secretion within CNS, possibly contributing to the neuronal degeneration in HIV-1 associated neurological disease.

Epitope Mapping of HIV1 gp41 Protein for Korean Anti - HIV1 Antisera using Synthetic Peptides / 대한면역학회지

The N-terminal sequence of HIV1 gp41 (amino acid residues 584-623) was known to be the immundominant region of HIV1 gp41 protein. In order to determine epitope for gp41 protein of Korean anti-HIV1 positive sera, multiple antigenic peptides (MAPs) for the sequences corresponding to 584-604, 590-612, 604-623 and 584-618 of HIV1 gp41 were synthesized by solid phase method using Fmoc-Lys (Fmoc)-OH and used as coating antigens for ELISA. The reactivities of the synthetic peptides with Korean HIV1 positive (21 samples) and anti-HIV1 negative sera (22 samples) obtained from healthy blood doner were estimated by an indirect ELISA. MAPs for 584-604, 590-612 and 604-623 of gp41 reacted with 62 %, 100 % and 81 % of Korean anti-HIV1 positive sera tested, respectively. The results suggest that the epitope for HIV1 gp 41 for Korean anti-HIV1 positive sera is located in the region of amino acid 590-612 of gp41. MAP for gp41 (584-618) reacted with all (100 %) of anti-HIV1 positive sera tested, but did not react with anti-HlV1 negative sera. In addition, this MAP reacted stronger with seven samples of anti-HIV1 positive sera of anti-HIV1/2 combo performance panel than the mixture of 584-604, 590-612 and 604-623 of gp41, but did not react with anti-HIV negative serum. The high sensitivity and selectivity of MAP of gp41 (584-618) suggest that this peptide as a coating antigen in an ELISA system will be useful for antibody detection of HIV1.

Isolation and structure analysis of streptomyces polysaccharide with inhibit HIV envelope glycoprotein subunit gp41 activity / 中国药理学通报

Aim To isolate, purify, and chemically characterize a polysaccharide showing inhibition of the six-?-helix bundle formation of HIV-1 envelope glycoprotein gp41 from cultured broth of a streptomyces sp.strain. Methods Ethanol was used to precipitate polysaccharides and macromolecules from the broth.Proteins in the precipitate were removed by sevage method.Purification was carried out by DEAE-Cellulose and sephadex G-25 column chromatography. The chemical structure of the polysaccharide was determined with the combined application of HPLC,UV,IR and 1H-NMR spectroscopy, and the methods of periodate oxidation and Smith degradation,etc. Activity of anti-HIV-1 ~gp41 six-?-helix bundle formation was assayed withsandwich ELISA method.Results The purified polysaccharide,designated as SMP for Streptomyces polysaccharide,is neutral with a molecular weight of approximately 4855 Daltons. Sugar analysis showed SMP contains glucose and fructose residues in an approximate molar ratio of 22∶1 (10.96 to 0.48). The glycosidic linkages were estimated to be (1→4)-?-D-pyranoside as its main chain, and 1→6 linkage was attached to the main chain. Activity analysis revealed SMP markedly inhibited the six-?-helix bundle formation of HIV-1 glycoprotein gp41 and the IC_~50 was (145.48?7.25) mg?L~-1 .Conclusion Streptomyces polysaccharide SMP showing inhibition of the six-?-helix bundle formation of HIV-1 envelope glycoprotein gp41 was isolated and purified.