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Publication Abstract from PubMed

Formation of catenanes by proteins is rare, with few known examples. We report herein the X-ray structure of a catenane dimer of lytic transglycosylase SltB1 of Pseudomonas aeruginosa. The enzyme is soluble and exists in the periplasmic space, where it modifies the bacterial cell wall. The catenane dimer exhibits the protein monomers in a noncovalent chain-link arrangement, whereby a stretch of 51 amino acids (to become a loop and three helices) from one monomer threads through the central opening of the structure of the partner monomer. The protein folds after threading in a manner that leaves two helices (alpha1 and alpha2) as stoppers to impart stability to the dimer structure. The symmetric embrace by the two SltB1 molecules occludes both active sites entirely, an arrangement that is sustained by six electrostatic interactions between the two monomers. In light of the observation of these structural motifs in all members of Family 3 lytic transglycosylases, catenanes might be present for those enzymes, as well. The dimeric catenane might represent a regulated form of SltB1.

X-ray Structure of Catenated Lytic Transglycosylase SltB1.,Dominguez-Gil T, Molina R, Dik DA, Spink E, Mobashery S, Hermoso JA Biochemistry. 2017 Nov 16. doi: 10.1021/acs.biochem.7b00932. PMID:29131935^[1]

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