title: Mycobacteriophage Ms6 LysB specifically targets the outer membrane of Mycobacterium smegmatis.
abstract: LysB, a mycobacteriophage Ms6-encoded protein, was previously identified as a lipolytic enzyme able to hydrolyse the ester bond in lipase and esterase substrates. In the present work, we show that LysB can hydrolyse lipids containing mycolic acids from the outer membrane of the mycobacterial cell wall. LysB was shown to hydrolyse the mycolic acids from the mycolyl-arabinogalactan-peptidoglycan complex where the mycolates of the inner leaflet of the outer membrane are covalently attached to an arabinosyl head group. In addition, treatment of the extractable lipids from Mycobacterium smegmatis, Mycobacterium bovis BCG and Mycobacterium tuberculosis H37Ra with LysB showed that trehalose 6,6'-dimycolate (TDM), a trehalose diester of two mycolic acid molecules, was hydrolysed by the enzyme. We have also determined the structures of the mycolic acid molecules that form the M. smegmatis TDM. The identification of a phage-encoded enzyme that targets the outer membrane of the mycobacterial cell wall enhances our understanding of the mechanism of mycobacteriophage lysis.
authors.affiliation: Centro de Patogénese Molecular, Unidade dos Retrovírus e Infecções Associadas Faculty of Pharmacy, University of Lisbon, Portugal.
authors.forename: Filipa
authors.initials: F
authors.lastname: Gil
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Anna E
authors.initials: AE
authors.lastname: Grzegorzewicz
authors.affiliation: Centro de Patogénese Molecular, Unidade dos Retrovírus e Infecções Associadas Faculty of Pharmacy, University of Lisbon, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Catalão
authors.affiliation: Centro de Patogénese Molecular, Unidade dos Retrovírus e Infecções Associadas Faculty of Pharmacy, University of Lisbon, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Vital
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: McNeil
authors.affiliation: Centro de Patogénese Molecular, Unidade dos Retrovírus e Infecções Associadas Faculty of Pharmacy, University of Lisbon, Portugal.
authors.forename: Madalena
authors.initials: M
authors.lastname: Pimentel
mesh_terms: D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism*; D004952:Esters / Q000378:metabolism; D005685:Galactans / Q000378:metabolism; D006868:Hydrolysis; D008563:Membrane Lipids / Q000378:metabolism; D009160:Mycobacteriophages / Q000201:enzymology*; D009163:Mycobacterium bovis / Q000378:metabolism; D020102:Mycobacterium smegmatis / Q000378:metabolism*; D009169:Mycobacterium tuberculosis / Q000378:metabolism; D009171:Mycolic Acids / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D013379:Substrate Specificity; D014199:Trehalose / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D004952:Esters; D005685:Galactans; D008563:Membrane Lipids; D009171:Mycolic Acids; D011135:Polysaccharides, Bacterial; D014764:Viral Proteins; D014199:Trehalose; C005653:arabinogalactan