RT Journal Article SR Electronic(1) A1 Gil, Filipa A1 Grzegorzewicz, Anna E. A1 Catalão, Maria João A1 Vital, João A1 McNeil, Michael R. A1 Pimentel, MadalenaYR 2010 T1 Mycobacteriophage Ms6 LysB specifically targets the outer membrane of Mycobacterium smegmatis JF Microbiology, VO 156 IS 5 SP 1497 OP 1504 DO https://doi.org/10.1099/mic.0.032821-0 PB Microbiology Society, SN 1465-2080, AB 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., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.032821-0