Structural and functional characterization of HP0377, a thioredoxin‐fold protein from Helicobacter pylori. (1st May 2013)

• Record Type: Journal Article
• Authors: Yoon, Ji Young; Kim, Jieun; An, Doo Ri; Lee, Sang Jae; Kim, Hyoun Sook; Im, Ha Na; Yoon, Hye‐Jin; Kim, Jin Young; Kim, Soon‐Jong; Han, Byung Woo; Suh, Se Won
• Is Part Of: Acta crystallographica. Volume 69:Part 5(2013:May)
• Page Start: 735
• Page End: 746
• Publication Date: 2013-05-01
• Subjects: Biomolecules -- Structure -- Periodicals; Physical biochemistry -- Periodicals; X-ray crystallography -- Periodicals; Crystallography -- Periodicals; 572
• DOI: 10.1107/S0907444913001236
• Languages: English
• ISSNs: 0907-4449

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Maturation of cytochrome <italic>c</italic> is carried out in the bacterial periplasm, where specialized thiol‐disulfide oxidoreductases provide the correct reduction of oxidized apocytochrome <italic>c</italic> before covalent haem attachment. HP0377 from <italic>Helicobacter pylori</italic> is a thioredoxin‐fold protein that has been implicated as a component of system II for cytochrome <italic>c</italic> assembly and shows limited sequence similarity to <italic>Escherichia coli</italic> DsbC, a disulfide‐bond isomerase. To better understand the role of HP0377, its crystal structures have been determined in both reduced and partially oxidized states, which are highly similar to each other. Sedimentation‐equilibrium experiments indicate that HP0377 is monomeric in solution. HP0377 adopts a thioredoxin fold but shows distinctive variations as in other thioredoxin‐like bacterial periplasmic proteins. The active site of HP0377 closely resembles that of <italic>E. coli</italic> DsbC. A reductase assay suggests that HP0377 may play a role as a reductase in the biogenesis of holocytochrome <italic>c</italic><sub>553</sub> (HP1227). Binding experiments indicate that it can form a covalent complex with HP0518, a putative L, D‐transpeptidase with a catalytic cysteine residue, <italic>via</italic> a disulfide bond. Furthermore, physicochemical properties of HP0377 and its R86A variant have been determined. These results suggest that HP0377 may perform multiple functions as a reductase in <italic>H. pylori</italic>.</p> </abstract>