Open AccessPurification and characterization of KpsT, the ATP‐binding component of the ABC‐capsule exporter of Escherichia coli K1
Author(s) -
Nsahlai Christiane J.,
Silver Richard P.
Publication year - 2003
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/s0378-1097(03)00428-2
Subject(s) - escherichia coli , atp hydrolysis , biochemistry , chemiosmosis , bacterial outer membrane , biology , cytoplasm , adenosine triphosphate , atp binding cassette transporter , chemistry , atpase , enzyme , atp synthase , gene , transporter
The K1 capsule, an α(2,8)‐linked polymer of sialic acid, is an important virulence determinant of invasive Escherichia coli . The 17‐kb kps gene cluster of E. coli K1 encodes the information necessary for capsule expression at the cell surface. Two proteins, KpsM and KpsT, play a role in the transport of capsular polysaccharide across the cytoplasmic membrane, utilizing the energy from ATP hydrolysis. They belong to the ATP‐binding cassette superfamily of transport proteins. In this study, we purified KpsT in its native form and show that the purified protein is able to bind ATP, undergo an ATP‐dependent conformational change and hydrolyze ATP. Protease accessibility studies demonstrate the in vivo interaction between KpsM and KpsT.