7k7f

From Proteopedia

Solution Structure of the Corynebacterium diphtheriae SpaA Pilin-Signal Peptide Complex

Structural highlights

7k7f is a 2 chain structure with sequence from Corynebacterium diphtheriae and Corynebacterium diphtheriae NCTC 13129. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Solution NMR, 20 models
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

Q6NF81_CORDI

Publication Abstract from PubMed

Gram-positive bacteria assemble pili (fimbriae) on their surfaces to adhere to host tissues and to promote polymicrobial interactions. These hair-like structures, although very thin (1 to 5 nm), exhibit impressive tensile strengths because their protein components (pilins) are covalently crosslinked together via lysine-isopeptide bonds by pilus-specific sortase enzymes. While atomic structures of isolated pilins have been determined, how they are joined together by sortases and how these interpilin crosslinks stabilize pilus structure are poorly understood. Using a reconstituted pilus assembly system and hybrid structural biology methods, we elucidated the solution structure and dynamics of the crosslinked interface that is repeated to build the prototypical SpaA pilus from Corynebacterium diphtheriae We show that sortase-catalyzed introduction of a K190-T494 isopeptide bond between adjacent SpaA pilins causes them to form a rigid interface in which the LPLTG sorting signal is inserted into a large binding groove. Cellular and quantitative kinetic measurements of the crosslinking reaction shed light onto the mechanism of pilus biogenesis. We propose that the pilus-specific sortase in C. diphtheriae uses a latch mechanism to select K190 on SpaA for crosslinking in which the sorting signal is partially transferred from the enzyme to a binding groove in SpaA in order to facilitate catalysis. This process is facilitated by a conserved loop in SpaA, which after crosslinking forms a stabilizing latch that covers the K190-T494 isopeptide bond. General features of the structure and sortase-catalyzed assembly mechanism of the SpaA pilus are likely conserved in Gram-positive bacteria.

Sortase-assembled pili in Corynebacterium diphtheriae are built using a latch mechanism.,McConnell SA, McAllister RA, Amer BR, Mahoney BJ, Sue CK, Chang C, Ton-That H, Clubb RT Proc Natl Acad Sci U S A. 2021 Mar 23;118(12):e2019649118. doi: , 10.1073/pnas.2019649118. PMID:33723052^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ McConnell SA, McAllister RA, Amer BR, Mahoney BJ, Sue CK, Chang C, Ton-That H, Clubb RT. Sortase-assembled pili in Corynebacterium diphtheriae are built using a latch mechanism. Proc Natl Acad Sci U S A. 2021 Mar 23;118(12):e2019649118. PMID:33723052 doi:10.1073/pnas.2019649118