6xi3

Publication Abstract from PubMed

RTX adhesins are long, multi-domain proteins present on the outer membrane of many Gram-negative bacteria. From this vantage point, adhesins use their distal ligand-binding domains for surface attachment leading to biofilm formation. To expand the reach of the ligand-binding domains, RTX adhesins maintain a central extender region of multiple tandem repeats, which makes up most of the proteins' large molecular weight. Alignments of the 10-15-kDa extender domains show low sequence identity between adhesins. Here we have produced and structurally characterized protein constructs of four tandem repeats (tetra-tandemers) from two different RTX adhesins. In comparing the tetra-tandemers to each other and already solved structures from Marinomonas primoryensis and Salmonella enterica, the extender domains fold as diverse beta-sandwich structures with widely differing calcium contents. However, all the tetra-tandemers have at least one calcium ion coordinated in the linker region between beta-sandwich domains whose role appears to be the rigidification of the extender region to help the adhesin extend its reach.

Essential role of calcium in extending RTX adhesins to their target.,Vance TDR, Ye Q, Conroy B, Davies PL J Struct Biol X. 2020 Sep 8;4:100036. doi: 10.1016/j.yjsbx.2020.100036., eCollection 2020. PMID:32984811^[1]

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