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Acta Crystallogr F Struct Biol Commun. 2017 Apr 1;73(Pt 4):202-208. doi: 10.1107/S2053230X17003004. Epub 2017 Mar 22.

Crystallization and X-ray analysis of the extracellular adhesion domain of Helicobacter pylori adhesin A: the significance of the cation composition in the crystallization precipitant.

Author information

1
Institute of Immunology, The Third Military Medical University, Chongqing 400038, People's Republic of China.
2
Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, The Third Military Medical University, Chongqing 400038, People's Republic of China.
3
Department of Anatomy and Embryology, Medical Division, Peking University, Beijing 100191, People's Republic of China.

Abstract

Adherence to host cells is a crucial step in the process of bacterial infection, which is usually mediated by a number of outer membrane proteins identified as adhesins. Helicobacter pylori adhesin A (HpaA) is a member of the adhesin family that mediates the adherence of Helicobacter pylori to gastric epithelial cells, and consequently assists the bacteria in becoming a life-long colonizer of the human stomach. In this study, two constructs were made for the production of truncated HpaA proteins comprising residues 31-260 and 53-260, respectively. The products of both constructs were crystallized, but only the protein from the shorter construct (residues 53-260) formed crystals that were capable of diffraction. In the subsequent optimization trials, crystals in different forms were unexpectedly obtained by using lithium sulfate and ammonium sulfate as the precipitant. An X-ray data set was collected to 1.95 Å resolution on beamline BL18U1 at SSRF using a crystal grown with 1.92 M lithium sulfate, which belonged to space group P65 with unit-cell parameters a = b = 95.42, c = 54.72 Å, γ = 120°, while another crystal grown with 1.9 M ammonium sulfate diffracted to 2.60 Å resolution and the collected data set was indexed in space group P21212, with unit-cell parameters a = 121.01, b = 190.56, c = 106.31 Å. The collection of diffraction data has established a solid basis for structure determination.

KEYWORDS:

Helicobacter pylori adhesin A; HpaA; adhesion domain; cations; crystallization

PMID:
28368278
PMCID:
PMC5379169
DOI:
10.1107/S2053230X17003004
[Indexed for MEDLINE]
Free PMC Article

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