title: A second endolysin gene is fully embedded in-frame with the lysA gene of mycobacteriophage Ms6.
abstract: Mycobacteriophages are dsDNA viruses that infect mycobacterial hosts. The mycobacteriophage Ms6 accomplishes lysis by producing two cell wall hydrolytic enzymes, Lysin A (LysA) that possesses a central peptidoglycan recognition protein (PGRP) super-family conserved domain with the amidase catalytic site, that cleaves the amide bond between the N-acetylmuramic acid and L-alanine residues in the oligopeptide crosslinking chains of the peptidoglycan and Lysin B (LysB) a mycolylarabinogalactan esterase that hydrolyzes the mycolic acids from the mycolyl-arabinogalactan-peptidoglycan complex. Examination of the endolysin (lysA) DNA sequence revealed the existence of an embedded gene (lysA(241)) encoded in the same reading frame and preceded by a consensus ribosome-binding site. In the present work we show that, even though lysA is essential for Ms6 viability, phage mutants that express only the longer (Lysin(384)) or the shorter (Lysin(241)) endolysin are viable, but defective in the normal timing, progression and completion of host cell lysis. In addition, both endolysins have peptidoglycan hydrolase activity and demonstrated broad growth inhibition activity against various gram-positive bacteria and mycobacteria.
authors.affiliation: Centro de Patogénese Molecular, Unidade dos Retrovírus e Infecções Associadas, Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Catalão
authors.forename: Catarina
authors.initials: C
authors.lastname: Milho
authors.forename: Filipa
authors.initials: F
authors.lastname: Gil
authors.forename: José
authors.initials: J
authors.lastname: Moniz-Pereira
authors.forename: Madalena
authors.initials: M
authors.lastname: Pimentel
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001433:Bacteriolysis / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D010450:Endopeptidases / Q000096:biosynthesis / Q000235:genetics*; D004926:Escherichia coli; D005814:Genes, Viral / Q000235:genetics*; D006868:Hydrolysis / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics; D009160:Mycobacteriophages / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D020102:Mycobacterium smegmatis / Q000187:drug effects / Q000821:virology; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000378:metabolism; D013997:Time Factors; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D014764:Viral Proteins; D010450:Endopeptidases; C001143:endolysin; D009238:N-Acetylmuramoyl-L-alanine Amidase