6Z05

Campylobacter jejuni serine protease HtrA

Summary for 6Z05

• Entry DOI: 10.2210/pdb6z05/pdb
• EMDB information: 11003
• Descriptor: DegQ family serine endoprotease (1 entity in total)
• Functional Keywords: campylobacter jejuni, serine protease, htra, dodecamer, lyase
• Biological source: Campylobacter jejuni
• Total number of polymer chains: 12
• Total formula weight: 566188.55

Authors

Grinzato, A.,Kandiah, E.,Zanotti, G. (deposition date: 2020-05-07, release date: 2020-09-30, Last modification date: 2024-05-15)

Primary citation

Zarzecka, U.,Grinzato, A.,Kandiah, E.,Cysewski, D.,Berto, P.,Skorko-Glonek, J.,Zanotti, G.,Backert, S.
Functional analysis and cryo-electron microscopy of Campylobacter jejuni serine protease HtrA.
Gut Microbes, 12:1-16, 2020

PubMed Abstract: is a predominant zoonotic pathogen causing gastroenteritis and other diseases in humans. An important bacterial virulence factor is the secreted serine protease HtrA (HtrA ), which targets tight and adherens junctional proteins in the gut epithelium. Here we have investigated the function and structure of HtrA using biochemical assays and cryo-electron microscopy. Mass spectrometry analysis identified differences and similarities in the cleavage site specificity for HtrA by comparison to the HtrA counterparts from and . We defined the architecture of HtrA at 5.8 Å resolution as a dodecamer, built of four trimers. The contacts between the trimers are quite loose, a fact that explains the flexibility and mobility of the dodecameric assembly. This flexibility has also been studied through molecular dynamics simulation, which revealed opening of the dodecamer to expose the proteolytically active site of the protease. Moreover, we examined the rearrangements at the level of oligomerization in the presence or absence of substrate using size exclusion chromatography, which revealed hexamers, dodecamers and larger oligomeric forms, as well as remarkable stability of higher oligomeric forms (> 12-mers) compared to previously tested homologs from other bacteria. Extremely dynamic decay of the higher oligomeric forms into lower forms was observed after full cleavage of the substrate by the proteolytically active variant of HtrA . Together, this is the first report on the in-depth functional and structural analysis of HtrA , which may allow the construction of therapeutically relevant HtrA inhibitors in the near future.

PubMed: 32960677
DOI: 10.1080/19490976.2020.1810532

Experimental method

ELECTRON MICROSCOPY (5.8 Å)