Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
J Biol Chem ; 281(26): 18193-200, 2006 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-16638752

RESUMO

Herpesviruses are the second leading cause of human viral diseases. Herpes Simplex Virus types 1 and 2 and Varicella-zoster virus produce neurotropic infections such as cutaneous and genital herpes, chickenpox, and shingles. Infections of a lymphotropic nature are caused by cytomegalovirus, HSV-6, HSV-7, and Epstein-Barr virus producing lymphoma, carcinoma, and congenital abnormalities. Yet another series of serious health problems are posed by infections in immunocompromised individuals. Common therapies for herpes viral infections employ nucleoside analogs, such as Acyclovir, and target the viral DNA polymerase, essential for viral DNA replication. Although clinically useful, this class of drugs exhibits a narrow antiviral spectrum, and resistance to these agents is an emerging problem for disease management. A better understanding of herpes virus replication will help the development of new safe and effective broad spectrum anti-herpetic drugs that fill an unmet need. Here, we present the first crystal structure of a herpesvirus polymerase, the Herpes Simplex Virus type 1 DNA polymerase, at 2.7 A resolution. The structural similarity of this polymerase to other alpha polymerases has allowed us to construct high confidence models of a replication complex of the polymerase and of Acyclovir as a DNA chain terminator. We propose a novel inhibition mechanism in which a representative of a series of non-nucleosidic viral polymerase inhibitors, the 4-oxo-dihydroquinolines, binds at the polymerase active site interacting non-covalently with both the polymerase and the DNA duplex.


Assuntos
DNA Polimerase Dirigida por DNA/química , Exodesoxirribonucleases/química , Herpesvirus Humano 1/enzimologia , Proteínas Virais/química , Aciclovir/química , Antivirais/química , Sítios de Ligação , Cristalografia , Desenho de Fármacos , Farmacorresistência Viral , Herpesvirus Humano 1/efeitos dos fármacos , Estrutura Quaternária de Proteína , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Quinolinas/química
2.
Bioconjug Chem ; 15(2): 333-43, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15025529

RESUMO

Screening of our compound collection identified PNU-92560, a 2-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxamide, as a novel antibacterial agent. Extensive analogue development identified that the 2-position of the thiadiazole could be functionalized with a linker that would allow the compound to be attached to a solid support. The extreme insolubility of the analogues prevented the mechanism of action for these compounds to be determined utilizing traditional methodology. The solid-supported compounds were utilized as affinity columns to identify elongation factor Tu (EF-Tu) as a putative target for this class of compounds. The activity of the compounds in a metabolic labeling experiments and in translation assay supports the identity of the target for these compounds to be EF-Tu.


Assuntos
Antibacterianos/química , Antibacterianos/metabolismo , Fator Tu de Elongação de Peptídeos/isolamento & purificação , Fator Tu de Elongação de Peptídeos/metabolismo , Pirimidinas/química , Tiazóis/química , Antibacterianos/farmacologia , Cromatografia de Afinidade , Cromatografia Líquida de Alta Pressão/métodos , Sistemas de Liberação de Medicamentos , Ligação Proteica/fisiologia , Pirimidinas/metabolismo , Pirimidinas/farmacologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/metabolismo , Tiazóis/metabolismo , Tiazóis/farmacologia
3.
Acta Crystallogr D Biol Crystallogr ; 58(Pt 12): 2153-6, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12454484

RESUMO

In bacteria the biosynthesis of all nascent polypeptides begins with N-formylmethionine. The post-translational removal of the N-formyl group is carried out by peptide deformylase (PDF). Processing of the N-formyl group from critical bacterial proteins is required for cell survival. This formylation/deformylation cycle is unique to eubacteria and is not utilized in eucaryotic cytosolic protein biosynthesis. Thus, inhibition of PDF would halt bacterial growth, spare host cell-function, and would be a novel mechanism for a new class of antibiotic. Diffraction-quality Se-met crystals of S. aureus PDF were prepared that belong to space group C222(1) with unit cell parameters of a = 94.1 b = 121.9 c = 47.6 A. Multiple anomalous dispersion data were collected at the Advanced Photon Source 17-ID beamline and used to solve the PDF structure to 1.9 A resolution. Crystals were also prepared with three PDF inhibitors: thiorphan, actinonin and PNU-172550. The thiorphan and actinonin co-crystals belong to space group C222(1) with similar unit-cell dimensions. Repeated attempts to generate a complex structure of PDF with PNU-172550 from the orthorhombic space group were unsuccessful. Crystallization screening identified an alternate C2 crystal form with unit-cell dimensions of a = 93.4 b = 42.5 c = 104.1 A, beta = 93 degrees.


Assuntos
Amidoidrolases , Aminopeptidases/química , Inibidores Enzimáticos/química , Staphylococcus aureus/enzimologia , Aminopeptidases/antagonistas & inibidores , Cristalização , Cristalografia por Raios X , Inibidores Enzimáticos/farmacologia , Conformação Proteica
4.
J Biol Chem ; 277(34): 31163-71, 2002 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-12048187

RESUMO

The first crystal structure of Class II peptide deformylase has been determined. The enzyme from Staphylococcus aureus has been overexpressed and purified in Escherichia coli and the structure determined by x-ray crystallography to 1.9 A resolution. The purified iron-enriched form of S. aureus peptide deformylase enzyme retained high activity over many months. In contrast, the iron-enriched form of the E. coli enzyme is very labile. Comparison of the two structures details many differences; however, there is no structural explanation for the dramatic activity differences we observed. The protein structure of the S. aureus enzyme reveals a fold similar, but not identical to, the well characterized E. coli enzyme. The most striking deviation of the S. aureus from the E. coli structure is the unique conformation of the C-terminal amino acids. The distinctive C-terminal helix of the latter is replaced by a strand in S. aureus which wraps around the enzyme, terminating near the active site. Although there are no differences at the amino acid level near the active site metal ion, significant changes are noted in the peptide binding cleft which may play a role in the design of general peptide deformylase inhibitors.


Assuntos
Amidoidrolases , Aminopeptidases/química , Proteínas de Bactérias/química , Staphylococcus aureus/enzimologia , Sequência de Aminoácidos , Aminopeptidases/antagonistas & inibidores , Cristalização , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Escherichia coli/enzimologia , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Estrutura Secundária de Proteína
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA