Assuntos
Vesícula/complicações , Epidermólise Bolhosa/complicações , Doenças Periodontais/complicações , Transtornos de Fotossensibilidade/complicações , Dermatoses do Couro Cabeludo/complicações , Idoso , Antibacterianos/administração & dosagem , Antibacterianos/uso terapêutico , Clobetasol/administração & dosagem , Clobetasol/uso terapêutico , Quimioterapia Combinada , Ácido Fusídico/administração & dosagem , Ácido Fusídico/uso terapêutico , Glucocorticoides/administração & dosagem , Glucocorticoides/uso terapêutico , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Rifampina/administração & dosagem , Rifampina/uso terapêutico , Dermatoses do Couro Cabeludo/tratamento farmacológico , Dermatoses do Couro Cabeludo/microbiologia , Resultado do TratamentoAssuntos
Anticorpos Monoclonais/uso terapêutico , Psoríase/tratamento farmacológico , Adulto , Idoso , Anticorpos Monoclonais Humanizados , Dermatite Esfoliativa/tratamento farmacológico , Dermatite Esfoliativa/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Psoríase/complicações , Psoríase/patologia , Indução de Remissão , Dermatopatias VesiculobolhosasRESUMO
The pK(a) values of the CXXC active-site cysteine residues play a critical role in determining the physiological function of the thioredoxin superfamily. To act as an efficient thiol-disulphide oxidant the thiolate state of the N-terminal cysteine must be stabilised and the thiolate state of the C-terminal cysteine residue destabilised. While increasing the pK(a) value of the C-terminal cysteine residue promotes oxidation of substrates, it has an inhibitory effect on the reoxidation of the enzyme, which is promoted by the formation of a thiolate at this position. Since reoxidation is essential to complete the catalytic cycle, the differential requirement for a high and a low pK(a) value for the C-terminal cysteine residue for different steps in the reaction presents us with a paradox. Here, we report the identification of a conserved arginine residue, located in the loop between beta5 and alpha4 of the catalytic domains of the human protein disulphide isomerase (PDI) family, which is critical for the catalytic function of PDI, ERp57, ERp72 and P5, specifically for reoxidation. An examination of the published NMR structure for the a domain of PDI combined with molecular dynamic studies suggest that the side-chain of this arginine residue moves into and out of the active-site locale and that this has a very marked effect on the pK(a) value of the active-site cysteine residues. This intra-domain motion resolves the apparent dichotomy of the pK(a) requirements for the C-terminal active-site cysteine.