Human ACE2 orthologous peptide sequences show better binding affinity to SARS-CoV-2 RBD domain: Implications for drug design.

Computational methods coupled with experimental validation play a critical role in the identification of novel inhibitory peptides that interact with viral antigenic determinants. The interaction between the receptor binding domain (RBD) of SARS-CoV-2 spike protein and the helical peptide of human angiotensin-converting enzyme-2 (ACE2) is a necessity for the initiation of viral infection. Herein, natural orthologs of human ACE2 helical peptide were evaluated for competitive inhibitory binding to the viral RBD by use of a computational approach, which was experimentally validated. A total of 624 natural ACE2 orthologous 32-amino acid long peptides were identified through a similarity search. Molecular docking was used to virtually screen and rank the peptides based on binding affinity metrics, benchmarked against human ACE2 peptide docked to the RBD. Molecular dynamics (MD) simulations were done for the human reference and the Nipponia nippon peptide as it exhibited the highest binding affinity (Gibbs free energy; -14 kcal/mol) predicted from the docking results. The MD simulation confirmed the stability of the assessed peptide in the complex (-12.3 kcal/mol). The top three docked-peptides (from Chitinophaga sancti, Nipponia nippon, and Mus musculus) and the human reference were experimentally validated by use of surface plasmon resonance technology. The human reference exhibited the weakest binding affinity (Kd of 318-441 pM) among the peptides tested, in agreement with the docking prediction, while the peptide from Nipponia nippon was the best, with 267-538-fold higher affinity than the reference. The validated peptides merit further investigation. This work showcases that the approach herein can aid in the identification of inhibitory biosimilar peptides for other viruses.

Investigation of the variability in the tool marks produced by modified blank firing pistols on fired 7.65 mm projectiles.

Firearms identification has an important place in forensic ballistic investigations since the weapons are widely used in criminal offences. Firearm examiners resolve many case files, through the use of automatic systems or comparison microscopes. Advanced forensic technologies like BALISTIKA helps to record and analyze non standard ballistic evidence. In today's world, with the ease of access to materials and production technique information, pistols modified from blank firers are frequently encountered as crime tools. In this study, the characteristics of 7.65 mm fired cartridge cases obtained by controlled shots from blank firing modified pistols were examined, and their detection performances were compared by means of the Balistika system. Although distinctive differences are not expected after successive test shootings, balistically important changes were seen after the use of blank firing modified pistols and the 3D imaging system proved to be useful in observing such differences. The analyses showed that the modifications in weapons lead to variation in the ballistic characteristics and reduce the accuracy of the detection performance, which may result in flawed forensic decisions. It was also found that the deviations in ballistic impressions of modified blank firing pistols were greater than that of standard fabricated and hand-made pistols. This unique study contributed to the forensic sciences literature by focusing on the impact of modified weapons on ballistic characteristics.

A recombinant Aspergillus oryzae fungus transmitted from larvae to adults of Anopheles stephensi mosquitoes inhibits malaria parasite oocyst development.

The control of malaria parasite transmission from mosquitoes to humans is hampered by decreasing efficacies of insecticides, development of drug resistance against the last-resort antimalarials, and the absence of effective vaccines. Herein, the anti-plasmodial transmission blocking activity of a recombinant Aspergillus oryzae (A. oryzae-R) fungus strain, which is used in human food industry, was investigated in laboratory-reared Anopheles stephensi mosquitoes. The recombinant fungus strain was genetically modified to secrete two anti-plasmodial effector peptides, MP2 (midgut peptide 2) and EPIP (enolase-plasminogen interaction peptide) peptides. The transstadial transmission of the fungus from larvae to adult mosquitoes was confirmed following inoculation of A. oryzae-R in the water trays used for larval rearing. Secretion of the anti-plasmodial effector peptides inside the mosquito midguts inhibited oocyst formation of P. berghei parasites. These results indicate that A. oryzae can be used as a paratransgenesis model carrying effector proteins to inhibit malaria parasite development in An. stephensi. Further studies are needed to determine if this recombinant fungus can be adapted under natural conditions, with a minimal or no impact on the environment, to target mosquito-borne infectious disease agents inside their vectors.

Expression and characterization of recombinant IL-1Ra in Aspergillus oryzae as a system.

BACKGROUND: The interleukin-1 receptor antagonist (IL-1Ra) is a crucial molecule that counteracts the effects of interleukin-1 (IL-1) by binding to its receptor. A high concentration of IL-1Ra is required for complete inhibition of IL-1 activity. However, the currently available Escherichia coli-expressed IL-1Ra (E. coli IL-1Ra, Anakinra) has a limited half-life. This study aims to produce a cost-effective, functional IL-1Ra on an industrial scale by expressing it in the pyrG auxotroph Aspergillus oryzae. RESULTS: We purified A. oryzae-expressed IL-1Ra (Asp. IL-1Ra) using ion exchange and size exclusion chromatography (53 mg/L). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that Asp. IL-1Ra is N-glycosylated and approximately 17 kDa in size. We conducted a comparative study of the bioactivity, binding kinetics, and half-life between Asp. IL-1Ra and E. coli IL-1Ra. Asp. IL-1Ra showed good bioactivity even at a low concentration of 0.5 nM. The in vitro half-life of Asp. IL-1Ra was determined for different time points (0, 24, 48, 72, and 96 h) and showed higher stability than E. coli IL-1Ra, despite exhibiting a 100-fold lower binding affinity (2 nM). CONCLUSION: This study reports the production of a functional Asp. IL-1Ra with advantageous stability, without extensive downstream processing. To our knowledge, this is the first report of a recombinant functional and stable IL-1Ra expressed in A. oryzae. Our results suggest that Asp. IL-1Ra has potential for industrial-scale production as a cost-effective alternative to E. coli IL-1Ra.

Development of etching paste for serial number restoration on aluminum engine block.

Engine numbers, which involve information regarding the engine type, production number, and year and place of manufacture, are used for identification purposes. Comprising of unique alphanumeric characters, the engine numbers are fully or partially obliterated especially in auto theft and smuggling cases to conceal the origin, identity, and owner of vehicles. The limitations of the current restoration techniques such as the difficulty of using chemical liquid etching in vertical sites, the restrictions of magnetic and optical methods, and the applicability of several techniques like electron backscatter diffraction only in the laboratory environment prompt the development of new techniques. In view of these limitations and the importance of restoring engine numbers in criminal investigations, this unique study aimed to develop an etching paste that would restore the effaced characters on a real aluminum alloy engine block. The characters which were cold-stamped on the engine block were milled at varying depths and restoration attempts were conducted using etching pastes formed with different chemicals and materials. The analyses indicate that the etching paste formed with 200 mg of perlite, 400 mg of iron powder, and 450 µL of 20 M NaOH provided restoration to a good extent. The prevention of over-etching through the controlling of the chemical reaction and the cost-effectiveness appears to be the advantages of this technique. The success of recovery on the real engine block, the facilitation of restoration on curved surfaces, and the chance of on-site usage will likely make the etching paste a widely used tool in serial number restoration.

Large-Scale Production of Anti-RNase A VHH Expressed in pyrG Auxotrophic Aspergillus oryzae.

Nanobodies, also referred to as VHH antibodies, are the smallest fragments of naturally produced camelid antibodies and are ideal affinity reagents due to their remarkable properties. They are considered an alternative to monoclonal antibodies (mAbs) with potential utility in imaging, diagnostic, and other biotechnological applications given the difficulties associated with mAb expression. Aspergillus oryzae (A. oryzae) is a potential system for the large-scale expression and production of functional VHH antibodies that can be used to meet the demand for affinity reagents. In this study, anti-RNase A VHH was expressed under the control of the glucoamylase promoter in pyrG auxotrophic A. oryzae grown in a fermenter. The feature of pyrG auxotrophy, selected for the construction of a stable and efficient platform, was established using homologous recombination. Pull-down assay, size exclusion chromatography, and surface plasmon resonance were used to confirm the binding specificity of anti-RNase A VHH to RNase A. The affinity of anti-RNase A VHH was nearly 18.3-fold higher (1.9 nM) when expressed in pyrG auxotrophic A. oryzae rather than in Escherichia coli. This demonstrates that pyrG auxotrophic A. oryzae is a practical, industrially scalable, and promising biotechnological platform for the large-scale production of functional VHH antibodies with high binding activity.

The effects of four different solvent vapours on the restoration of obliterated stamp markings from five different wooden surfaces.

The stamp markings on wooden surfaces, which are placed on trees and products including antiques, indicate the status of trees and involve identifying data regarding the products. Such markings are obliterated either to facilitate illegal logging or to conceal product information. Despite the wide literature on the restoration of obliterated characters on metal and polymer surfaces, the recovery of defaced characters on wooden surfaces appears to be understudied. Several reference texts in the forensic marks' examination literature suggest that water, water vapor, and alkaline solutions are useful in restoring the abraded markings on the wood. Since there does not seem to be any experimental study proving such success, this study aimed to fill this gap. This study conducted experimental research by using water, ethanol, ammonia, and chloroform to recover the scraped characters on samples obtained from walnut, beech, spruce, oak, and cedar trees. The cold-stamped characters, which were defaced at varying depths, were restored using vapor and liquid phases of four solvents. While the vapor phases of water, ethanol, and ammonia yielded good outcomes on all types of wooden surfaces, the liquid phases did not seem to be useful in the revisualization process. The response of the vapors, which varied between 62 and 220 s, depended on the type of wood. The restoration technique developed in this research offers the possibility of on-site usage, easy application, utilization of low-cost solvents, rapid recovery, and effectiveness on various wooden surfaces. Overall, the restoration methodology used in this research appears to be fruitful in retrieving identifying information on wooden samples.

Evaluation of the temporomandibular joint morphology and condylar position with cone-beam computerized tomography in patients with internal derangement.

OBJECTIVES: To evaluate the relationship between internal derangement and morphological features of the temporomandibular joint by comparing joint morphology between patients with ID and control patients. METHODS: The current study prospectively is evaluated the cone-beam computed images of 106 ID patients and 122 patients with asymptomatic joints; recorded angular and linear measurements. The relationships between these measurements and ID are investigated; the differences between the two groups using paired t tests. RESULTS: There were significant differences in the values of articular slope and the condyle height/glenoid fossa depth (CH/GFD) ratio between patients in the ID and control groups (p < 0.05). There was also a relationship between these parameters and the gender of patients with ID. The condylar position was posterior in the ID group. CONCLUSION: Posteriorly and superiorly located condyles with an increased CH/GFD ratio, condyles located eccentrically, and a steeper posterior slope may be risk factors for ID.

Direct Pulp Capping of Primary Molars with Calcium Hydroxide or MTA Following Hemorrhage Control with Different Medicaments: Randomized Clinical Trial.

Purpose: This study aimed to evaluate the effects of different medicaments (sterile saline [SS]; ferric sulfate [FS]; or sodium hypochlorite [SH]) and pulp capping materials (calcium hydroxide [CH] or mineral trioxide aggregate [MTA]) on the success of direct pulp capping (DPC) in primary molars. Methods: The study was conducted with 55 children aged four to eight years. A total of 118 teeth, in which occlusal caries removal resulted in pulp exposure, were treated with DPC across six groups: SS+CH; FS+CH; SH+CH; SS+MTA; FS+MTA; and SH+MTA. Teeth were restored with Class I composite resin. Results: After two years, the overall clinical and radiographical success for DPC were 94.1 percent (111 out of 118 teeth) and 88.9 percent (105 out of 118 teeth), respectively. The clinical and radiographical success, respectively, for hemorrhage control medicaments were 92.1 percent and 89.5 percent for SS, 92.5 percent and 82.5 percent for FS, 97.5 percent, and 95.0 percent for SH (P>0.05). Internal resorption was significantly higher in the FS+CH group when compared to other groups (P<0.05). MTA had significantly higher success than CH for clinical (98.3 percent versus 89.7 percent) and radiographical success (98.3 percent versus 79.3 percent) (P<0.05, each comparison). Conclusions: For primary molars with occlusal caries and less than one-mm exposure sites, these findings suggest that direct pulp capping with MTA following hemorrhage control with the tested solutions offers a more predictable outcome compared to CH. Further, the findings of this study indicate an increased risk for internal resorption when FS and CH are used for DPC.

Ferric sulfate pulpotomy in primary teeth with different base materials: a 2-year randomized controlled trial.

OBJECTIVE: To evaluate the effects of zinc oxide-eugenol, calcium hydroxide, and mineral trioxide aggregate as base materials on the clinical and radiographic success of ferric sulfate pulpotomies in primary molars. METHOD AND MATERIALS: Following hemostasis with 15.5% ferric sulfate, 105 teeth were randomly allocated to three groups: Group 1, zinc oxide-eugenol; Group 2, calcium hydroxide; and Group 3, mineral trioxide aggregate. All teeth were restored with stainless-steel crowns. Clinical and radiographic examinations were conducted at 6, 12, 18, and 24 months. RESULTS: After 24 months, clinical success rates for Groups 1 to 3 were 97.1% (34/35 teeth), 94.2% (33/35 teeth), and 97.1% (34/35 teeth), respectively (P > .05). Radiographic success rates were 65.7% (23/35 teeth), 65.7% (23/35 teeth), and 77.1% (27/35 teeth), respectively (P > .05). Internal resorption was the most observed radiographic finding (15/105 teeth). CONCLUSIONS: The choice of zinc oxide-eugenol, calcium hydroxide, and mineral trioxide aggregate, as base materials, did not affect the clinical and radiographic success of ferric sulfate pulpotomies in primary teeth.

A spectroscopic approach for rapid and simple serial number restoration on polyamide 6 parts of firearms: The use of video spectral comparator 8000.

Serial numbers have forensic value as they help to identify firearms. While the serial numbers are mostly stamped on the metal parts of firearms, the characters on polymer parts involve non-serial number information such as caliber, brand, model, or proof marks, which also serve for identification purposes. The forensic evidence indicates that the polymer frames of firearms bearing non-serial number information are obliterated through heating and scraping. Although the destructive restoration techniques for polymers are well-documented, there is little theoretical and practical knowledge regarding the non-destructive restoration techniques applied on polymers. In view of this gap, this study aims to devise a non-destructive spectral technique to recover the obliterated characters on Polyamide 6. Considering its wide use on polymers, the numbering is carried out by hot stamping and the numbers are defaced through heating, scraping, and hammering both superficially and deeply at varying depths. Herein, we focused on imitating the manual obliteration techniques used by criminals instead of the deepness-controlled techniques preferred by previous studies. The samples are then viewed under the UV and IR lights in the Video Spectral Comparator 8000 for the first time. The results suggest that spectral imaging provided restoration to a good extent after heating and scraping which made the characters invisible at a relatively low depth of deformation compared to hammering. The recovery of characters with this novel technique brings a new perspective forensic marks examination literature by producing quick, successful and reliable results and facilitating reexamination by not harming the sample.

The influence of voxel size and artifact reduction on the detection of vertical root fracture in endodontically treated teeth.

OBJECTIVE: The aim of this study was to evaluate the effect of voxel size and artefact reduction (AR) on the identification of vertical root fractures (VRFs) in endodontically treated teeth. METHODS: A total of a hundred sound, extracted human mandibular single-rooted premolars were decoronated, after which root canal preparation was performed, canals were filled with gutta percha by single cone technique. Randomly selected fifty specimens were fractured, repositioned and glued together. The teeth were examined with cone beam computed tomography (CBCT) in five different voxel sizes (0.125, 0.200, 0.250, 0.300, and 0.400 voxels). Two scans were performed for each tooth, one with AR and one without AR. Two radiologists evaluated the CBCT scans. RESULTS: All voxel dimensions were successful in detecting VRFs in CBCT scans. But as the voxel size increased, the percentage of detecting VRFs decreased. High accuracy, sensitivity, specificity and predictive values were found for VRF detection on CBCT scans. Accuracy and sensitivity values decreased (from 100 to 82) while voxel dimensions increased (from 0.125 to 0.400). High-resolution images (0.125, 0.200, and 0.250 voxels) caused an increase in sensitivity for detection of VRFs. AR did not affect the accuracy, sensitivity, specificity and predictive values for VRF detection on CBCT scans. CONCLUSIONS: High-resolution CBCT images resulted in an increase in sensitivity and specificity for detection of VRFs compared with lower-resolution CBCT images. The use of AR did not further improve its diagnostic potential.

Evaluation of radiomorphometric indices and bone findings on panoramic images in patients with scleroderma.

OBJECTIVES: The aim of this study was to make radiomorphometric measurements on panoramic images and evaluate the radiologic findings of bones and teeth in patients with scleroderma. STUDY DESIGN: Panoramic images of 49 patients with scleroderma and 51 healthy controls were assessed. Mandibular radiomorphometric indices, including mandibular cortical index (MCI), mental index (MI), panoramic mandibular index (PMI), gonial index (GI), and antegonial index (AI), were determined. Furthermore, mandibular osteolysis, changes of periodontal ligament (PDL) space and changes in the lamina dura were recorded for the scleroderma group. RESULTS: Statistically significant differences were found for MCI (P = .003), MI (P = .001), and PMI (P < .001) between the scleroderma and control groups, but not for GI or AI (P > .05). Widening of the PDL space (79.6%), thickening of the lamina dura (44.9%), limited mouth opening (71.4%), and osseous resorption of the mandible (8%) were detected in the scleroderma group. CONCLUSIONS: The radiomorphometric indices determined in the present study can be used on panoramic images to identify the existence of a porous structure in the mandibular cortical bone in patients with scleroderma. The most common prevalent oral radiographic manifestations of scleroderma were widening of the PDL space and of the lamina dura.

Facilitators and barriers to referral compliance among dental patients with increased risk of obstructive sleep apnea.

OBJECTIVE: Our aims were to determine the adherence rate to dentist referrals for sleep apnea evaluation and the barriers and facilitators to referral compliance. MATERIAL AND METHODS: A sample of 1099 patients was screened with the STOP-Bang questionnaire. Those with elevated risk were referred for a sleep evaluation. An interview was conducted over the phone to determine compliance to referral and the barriers and facilitators to compliance. RESULTS: Of the 1099 patients (mean age: 45.1 ± 10 years) screened, 224 (20.4%) patients were determined to be at-risk for obstructive sleep apnea (OSA). Only 41 (18.3%) patients with increased risk adhered to referral recommendation. Demographic and health characteristics did not show significant differences between the compliant and non-compliant patients. The most common facilitators to compliance were increased awareness about OSA (N = 25, 65%) and dentist recommendation (N = 14, 34.1%), whereas the most common barriers to referral compliance were misconceptions about OSA (N = 69, 37.7%) and work responsibilities (N = 44, 24%). CONCLUSIONS: Only a small percentage of patients adhered to the recommendation of their dentist to see a sleep specialist. Increased awareness about OSA and dentist recommendation were the most common factors that facilitated compliance, whereas misconceptions about OSA and work responsibilities were the most common barriers to patient compliance.

Partial Pulpotomy in Immature Permanent Molars After Carious Exposures Using Different Hemorrhage Control and Capping Materials.

PURPOSE: This study compared the outcome of partial pulpotomies with mineral trioxide aggregate (MTA) or calcium hydroxide (CH) following hemorrhage control with 2.5 percent sodium hypochlorite (SH) or 0.9 percent sterile saline (SS) solutions in cariously exposed immature permanent molars. METHODS: Following removal of two to three mm of the pulp at the exposure site, 80 Class I cavities were randomly allocated to four groups according to the hemorrhage control agent and pulp-capping material used: (1) group one-SH plus MTA; (2) group two-SS plus MTA; (3) group three-SH plus CH; (4) group four-SS plus CH. Glass ionomer cement was applied over the pulp-capping material, and the teeth were later restored with composite resin. The patients were recalled at six, 12, 18, and 24 months. RESULTS: After 24 months, simultaneous radiographic and clinical success rates were 94.4 percent, 100 percent, 95 percent, and 100 percent for groups one to four, respectively (P>.05). No significant correlation was found between marginal integrity scores of restorations and partial pulpotomy failure (P>.05). CONCLUSIONS: Partial pulpotomy, performed with MTA or CH used as the pulp-capping material following hemostasis with SH or SS solutions, provided comparable and favorable outcomes in carious pulp exposures of immature permanent teeth.

Implant-Site Related and Patient-Based Factors With the Potential to Impact Patients' Satisfaction, Quality of Life Measures and Perceptions Toward Dental Implant Treatment.

OBJECTIVES: The present study aimed at evaluating both the implant site-related and patient-based factors with the potential to affect the extent of patients' satisfaction and also their perceptions regarding dental implant treatment. Potential differences between the esthetic evaluations of dental patients and dental specialists were also considered. MATERIALS AND METHODS: Implant-supported fixed prosthesis (n = 164) in 264 anterior esthetic implant sites were included. Patients' satisfaction, esthetic considerations, and perceptions toward dental implants, were evaluated by both Oral Health Impact Profile-14 (OHIP-14) questionnaire and visual analog scale. Pink Esthetic Score/White Esthetic Score were used for the professional esthetic evaluations of dental specialists. RESULTS: Overall patient satisfaction was high (87.42 ± 11.86). Compared with implant supported single-tooth restorations, patients with implant-supported bridges had lower OHIP scores (P = 0.001) and were relatively less satisfied with particular aspects of dental implant treatment (eg, cleanability, phonetics, surgical discomfort, and pretreatment information). Generally, type of prosthesis, history of soft/hard tissue augmentation, and reason for tooth loss had a clear impact on the extent of patients' satisfaction, esthetic considerations regarding treatment outcome, and their perceptions toward dental implant treatment (P < 0.05). CONCLUSIONS: Fixed implant-supported restorations generally provide with high levels of satisfaction and oral health-related quality of life.

Randomized Clinical Trial of Composite Restorations in Primary Teeth: Effect of Adhesive System after Three Years.

The purpose of this study was to assess the clinical performance of composite restorations placed with different adhesive systems in primary teeth. In 32 patients, 128 composite restorations were placed using a split-mouth design as follows (4 groups/patient): three-step etch-and-rinse (Group 1), two-step etch-and-rinse (Group 2), two-step self-etch (Group 3), and one-step self-etch (Group 4). The restorations were clinically evaluated at baseline and at 6, 18, and 36 months according to the FDI criteria. There was no significant difference between the adhesive systems in retention of the restorations (p > 0.05). Over time, there was a statistically significant decrease in marginal adaptation in all groups, whereas surface and marginal staining significantly increased in Groups 3 and 4 (p < 0.05). The etch-and-rinse adhesive systems resulted in better marginal adaptation than the self-etch adhesive systems (p < 0.05). It was concluded that preetching of the primary enamel might help improve the clinical performance of the self-etch adhesive systems in primary teeth.

Radiographic Fractal and Clinical Resonance Frequency Analyses of Posterior Mandibular Dental Implants: Their Possible Association With Mandibular Cortical Index With 12-Month Follow-up.

BACKGROUND: The aim of the present study was to investigate whether the mandibular cortical index (MCI) has a relationship with fractal dimension of bone and/or implant stability, and to justify the possible association between MCI, fractal dimension, and stability. MATERIALS AND METHODS: Eighty-two subjects who received dental implants to replace missing mandibular premolar/molar sites were selected. Three months after surgical placement, implants were restored with fixed ceramic fused metal crowns. MCI was evaluated at baseline; fractal dimensions were measured with fractal analysis (FA) and implant stability quotient (ISQ) with resonance frequency analysis immediately after surgery and 12-month follow-up. RESULTS: FA at mesial and distal regions for Class 1, Class 2, and Class 3 MCI resulted with significant increases at 12-month follow-up compared to baseline. The ISQ in patients with Class 2 and Class 3 MCI resulted with a significant decrease compared to Class 1 MCI at baseline and at 12 months. All MCI classes evaluated with ISQ and FA at baseline values resulted with significant increases at 12 months. Significant correlations were considered for all mandibular posterior implants between baseline and 12-month measurements for ISQ and FA evaluations. CONCLUSIONS: Fractal analysis may be a useful method for understanding the healing process around implants and implant stability quotient values. Mandibular cortical index evaluations should be considered before implant procedures, which may provide a presurgical treatment plan and may provide information about the mandibular bone quality.

The Preserved HTH-Docking Cleft of HIV-1 Integrase Is Functionally Critical.

HIV-1 integrase (IN) catalyzes viral DNA integration into the host genome and facilitates multifunctional steps including virus particle maturation. Competency of IN to form multimeric assemblies is functionally critical, presenting an approach for anti-HIV strategies. Multimerization of IN depends on interactions between the distinct subunit domains and among the flanking protomers. Here, we elucidate an overlooked docking cleft of IN core domain that anchors the N-terminal helix-turn-helix (HTH) motif in a highly preserved and functionally critical configuration. Crystallographic structure of IN core domain in complex with Fab specifically targeting this cleft reveals a steric overlap that would inhibit HTH-docking, C-terminal domain contacts, DNA binding, and subsequent multimerization. While Fab inhibits in vitro IN integration activity, in vivo it abolishes virus particle production by specifically associating with preprocessed IN within Gag-Pol and interfering with early cytosolic Gag/Gag-Pol assemblies. The HTH-docking cleft may offer a fresh hotspot for future anti-HIV intervention strategies.