Structure and chemistry of lysinoalanine crosslinking in the spirochaete flagella hook.

ABSTRACT: The flagellar hook protein FlgE from spirochaete bacteria self-catalyzes the formation of an unusual inter-subunit lysinoalanine (Lal) crosslink that is critical for cell motility. Unlike other known examples of Lal biosynthesis, conserved cysteine and lysine residues in FlgE spontaneously react to form Lal without the involvement of additional enzymes. Oligomerization of FlgE via its D0 and Dc domains drives assembly of the crosslinking site at the D1-D2 domain interface. Structures of the FlgE_D2 domain, dehydroalanine (DHA) intermediate and Lal crosslinked FlgE subunits reveal successive snapshots of the reaction. Cys178 flips from a buried configuration to release hydrogen sulfide (H₂S/HS^-) and produce DHA. Interface residues provide hydrogen bonds to an

SUBMITTER: Lynch MJ 

PROVIDER: S-EPMC6764852 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature