title: Single mutation on the surface of Staphylococcus aureus Sortase A can disrupt its dimerization.
abstract: Staphylococcus aureus Sortase A (SrtA) is an important Gram-positive membrane enzyme which catalyzes the anchoring of many cell surface proteins conserved with the LPXTG sequence. Recently SrtA has been demonstrated to be a dimer with a Kd of 55 microM in vitro. Herein, we show that a single point mutation of amino acid residue on the surface of SrtA can completely disrupt the dimerization. Native polyacrylamide gel electrophoresis and analytical gel filtration chromatography were used to detect the dimer-monomer equilibrium of SrtA mutants. Circular dichroism spectrum experiments were performed to study the conformational change of each SrtA mutant. An enzyme activity assay confirmed that all the SrtA mutants were active in vitro. Our results not only are important for understanding the SrtA protein self-associating mechanism but also provided the necessary starting materials for the study of sortase A pathway in vivo, which may have significant implications for discovering microbial physiology and give a potential target for novel Gram-positive antibiotics.
authors.affiliation: Division of Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.forename: Changsheng
authors.initials: C
authors.lastname: Lu
authors.forename: Matthew
authors.initials: M
authors.lastname: Standland
authors.forename: Eric
authors.initials: E
authors.lastname: Lai
authors.forename: Gabrielle N
authors.initials: GN
authors.lastname: Moreno
authors.forename: Aiko
authors.initials: A
authors.lastname: Umeda
authors.forename: Xudong
authors.initials: X
authors.lastname: Jia
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D019881:Aminoacyltransferases / Q000737:chemistry* / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics*; D001483:Base Sequence; D002850:Chromatography, Gel; D002942:Circular Dichroism; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000235:genetics*; D017931:DNA Primers; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D013211:Staphylococcus aureus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D019881:Aminoacyltransferases; C120542:sortase A; D003546:Cysteine Endopeptidases