10 research outputs found
Expression, Purification, Structural and Functional Analysis of SycB: A Type Three Secretion Chaperone From Yersinia Enterocolitica
In Yersinia enterocolitica biovar 1B, a genome
encoded TTSS designated as Ysa-Ysp system is used for
virulence. SycB is an annotated chaperone to this system.
SycB is soluble in presence of translocator YspC. SycB and
its truncated form (DSycB(1–114)) exist as dimers. YspC
forms a 1:1 complex with SycB. Homology model of SycB
shows a flexible N-terminal may be required for solubility
and dimerization; and concave core formed by antiparallel
helices of TPRs. Far UV CD spectra confirm that SycB is
predominantly alpha helical. Near UV CD spectra show that
SycB has tertiary structure at pH 7.2 (native folded protein),
which disappears at pH 5 (molten globule) and SycB
releases YspC at pH 5. SycB has a cooperative melting
behavior. At pH 7.2, SycB shows solvent accessible
hydrophobic patches. Concave core in the model exhibits
ANS binding within FRET distance of tyrosines in the TPR,
allowing a range of interaction of SycB with its ligand
The Yersinia Ysc-Yop 'type III' weaponry
'Type III secretion'--the mechanism by which some pathogenic bacteria inject proteins straight into the cytosol of eukaryotic cells to 'anaesthetize' or 'enslave' them--was discovered in 1994. Important progress has been made in this area during the past few years: the bacterial organelles responsible for this secretion--called 'injectisomes'--have been visualized, the structures of some of the bacterial protein 'effectors' have been determined, and considerable progress has been made in understanding the intracellular action of the effectors. Type III secretion is key to the pathogenesis of bacteria from the Yersinia genus