Extracellular pullulanase of Klebsiella pneumoniae is a lipoprotein.

AUTOR(ES)

Pugsley, A P

RESUMO

Pullulanase is a starch-debranching enzyme produced by the gram-negative bacterium Klebsiella pneumoniae. In this organism, the enzyme is first exported to the outer membrane and is subsequently released into the growth medium. Evidence reported here indicates that pullulanase is a lipoprotein. It is apparently synthesized as a precursor with a 19-residue-long signal sequence and modified by the covalent attachment of palmitate to the cysteine residue which becomes the amino terminus after cleavage of the signal sequence. In this respect, pullulanase is similar to some penicillinases produced by gram-positive bacteria which are initially exported to the cell surface and subsequently released into the medium. However, pullulanase and the penicillinases differ in one important aspect, namely, that the extracellular pullulanase still carries the covalently attached fatty acyls, whereas extracellular penicillinases lack the modified amino-terminal cysteine together with a limited number of other residues from the amino terminus.

Documentos Relacionados

• Klebsiella pneumoniae pulS gene encodes an outer membrane lipoprotein required for pullulanase secretion.
• Cloning and expression in Escherichia coli of the Klebsiella pneumoniae genes for production, surface localization and secretion of the lipoprotein pullulanase.
• Lactococcal proteinase maturation protein PrtM is a lipoprotein.
• The Chlamydia trachomatis Mip-like protein is a lipoprotein.
• The 34-kilodalton membrane immunogen of Treponema pallidum is a lipoprotein.