Utilize este identificador para referenciar este registo: http://hdl.handle.net/10451/20939
Título: The lytic cassette of mycobacteriophage Ms6 encodes an enzyme with lipolytic activity
Autor: Gil, Filipa
Catalao, Maria Joao
Moniz-Pereira, Jose
Leandro, Paula
McNeil, Michael
Pimentel, Madalena
Palavras-chave: Microbiology
Data: 2008
Citação: MICROBIOLOGY-SGM. - Vol. 154, Part 5 (MAY 2008), p. 1364-1371
Resumo: dsDNA bacteriophages use the dual system endolysin-holin to achieve lysis of their bacterial host. In addition to these two essential genes, some bacteriophages encode additional proteins within their lysis module. In this report, we describe the activity of a protein encoded by gene lysB from the mycobacteriophage Ms6. lysB is localized within the lysis cassette, between the endolysin gene (lysA) and the holin gene (hol). Analysis of the deduced amino acid sequence of LysB revealed the presence of a conserved motif (Gly-Tyr-Ser-Gin-Gly) characteristic of enzymes with lipolytic activity. A BLAST search within the sequences of protein databases revealed significant similarities to other putative proteins that are encoded by mycobacteriophages only, indicating that LysB and those proteins may be specific to their mycobacterial hosts. A screening for His(6)-LysB activity on esterase and lipase substrates confirmed the lipolytic activity. Examination of the kinetic parameters of recombinant His(6)-LysB for the hydrolysis of p-nitrophenyl esters indicated that although this protein could use a wide range of chain length substrates (C-4-C-18), it presents a higher affinity for p-nitrophenyl esters of longer chain length (C-16 and C-18). Using p-nitrophenyl butyrate as a substrate, the enzyme showed optimal activity at 23 degrees C and pH 7.5-8.0. Activity was increased in the presence of Ca2+ and Mn2+. To the best of our knowledge, this is the first description of a protein with lipolytic activity encoded within a bacteriophage.
URI: http://hdl.handle.net/10451/20939
DOI: http://dx.doi.org/10.1099/mic.0.2007/014621-0
ISSN: 1350-0872
Aparece nas colecções:FF - Produção Científica 2000-2009

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