Assuntos
Proteínas Arqueais , Peptídeo Hidrolases/isolamento & purificação , Pyrococcus furiosus/enzimologia , Proteínas Recombinantes de Fusão/isolamento & purificação , Cromatografia Líquida/métodos , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Peso Molecular , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismoAssuntos
Endopeptidases/isolamento & purificação , Thermotoga maritima/enzimologia , Sequência de Aminoácidos , Biopolímeros , Cromatografia Líquida/métodos , Endopeptidases/química , Endopeptidases/metabolismo , Microscopia Eletrônica , Dados de Sequência Molecular , Homologia de Sequência de AminoácidosRESUMO
A novel homomultimeric protease (> 669 kDa), based on 31 kDa subunits, was purified from cell extracts of the hyperthermophilic bacterium Thermotoga maritima. This protease exhibits activity toward chymotrypsin and trypsin substrates, optimally at 90 degrees C and pH 7.1, and has a half-life of 36 min at 95 degrees C. Transmission electron microscopy established that the protease consists of a large globular assembly which appears circular from the front view. The function of this protease in T. maritima remains unclear, although putative homologs include a 29 kDa antigen from Mycobacterium tuberculosis and a 31 kDa monomer of a high molecular weight bacteriocin produced by Brevibacterium linens [Valdes-Stauber, N. and Scherer, S. (1996) Appl. Environ. Microbiol. 62, 1283-1286]. The relationship of these mesophilic proteins to the T. maritima protease suggests that their antibacterial activity may involve elements of proteolysis, and raises the prospect for antimicrobial ecological strategies in hyperthermophilic niches.
