Structural basis for the kexin-like serine protease from Aeromonas sobria as sepsis-causing factor.

Abstract

The anaerobic bacterium Aeromonas sobria is known to cause potentially lethal septic shock. We recently proposed that A. sobria serine protease (ASP) is a sepsis-related factor that induces vascular leakage, reductions in blood pressure via kinin release, and clotting via activation of prothrombin. ASP preferentially cleaves peptide bonds that follow dibasic amino acid residues, as do Kex2 (Saccharomyces cerevisiae serine protease) and furin, which are representative kexin family proteases. Here, we revealed the crystal structure of ASP at 1.65 A resolution using the multiple isomorphous replacement method with anomalous scattering. Although the overall structure of ASP resembles that of Kex2, it has a unique extra occluding region close to its active site. Moreover, we found that a nicked ASP variant is cleaved within the occluding region. Nicked ASP shows a greater ability to cleave small peptide substrates than the native enzyme. On the other hand, the cleavage pattern for prekallikrein differs from that of ASP, suggesting the occluding region is important for substrate recognition. The extra occluding region of ASP is unique and could serve as a useful target to facilitate development of novel antisepsis drugs.

• Authors: Hidetomo Kobayashi, Hiroko Utsunomiya, Hiroyasu Yamanaka, Yoshihisa Sei, Nobuhiko Katunuma, Keinosuke Okamoto, Hideaki Tsuge
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 284 Issue 40 Pg. 27655-63 (Oct 02 2009) ISSN: 1083-351X [Electronic] United States
• PMID: 19654332 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Virulence Factors
• Serine Endopeptidases
• Subtilisin
• Furin

Topics

• Aeromonas (enzymology)
• Amino Acid Sequence
• Antisepsis
• Catalytic Domain
• Crystallography, X-Ray
• Furin (chemistry)
• Mass Spectrometry
• Models, Molecular
• Molecular Sequence Data
• Protein Structure, Tertiary
• Sepsis (microbiology)
• Serine Endopeptidases (chemistry, metabolism)
• Substrate Specificity
• Subtilisin (chemistry)
• Virulence Factors (chemistry, metabolism)