X-ray Structure of Catenated Lytic Transglycosylase SltB1

TY - JOUR

T1 - X-ray Structure of Catenated Lytic Transglycosylase SltB1

AU - Domínguez-Gil, Teresa

AU - Molina, Rafael

AU - Dik, David A

AU - Spink, Edward

AU - Mobashery, Shahriar

AU - Hermoso, Juan A

PY - 2017/12/5

Y1 - 2017/12/5

N2 - 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 (α1 and α2) 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.

AB - 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 (α1 and α2) 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.

KW - Bacterial Proteins/chemistry

KW - Crystallography, X-Ray

KW - Models, Molecular

KW - Peptidoglycan Glycosyltransferase/chemistry

KW - Protein Conformation

KW - Protein Folding

U2 - 10.1021/acs.biochem.7b00932

DO - 10.1021/acs.biochem.7b00932

M3 - Journal article

C2 - 29131935

SN - 0006-2960

VL - 56

SP - 6317

EP - 6320

JO - Biochemistry

JF - Biochemistry

IS - 48

ER -