PMID:14506276

Citation	Wang, ZM, Li, X, Cocklin, RR, Wang, M, Wang, M, Fukase, K, Inamura, S, Kusumoto, S, Gupta, D and Dziarski, R (2003) Human peptidoglycan recognition protein-L is an N-acetylmuramoyl-L-alanine amidase. J. Biol. Chem. 278:49044-52
Abstract	Peptidoglycan recognition proteins (PGRPs) are pattern recognition molecules coded by up to 13 genes in insects and 4 genes in mammals. In insects PGRPs activate antimicrobial pathways in the hemolymph and cells, or are peptidoglycan (PGN)-lytic amidases. In mammals one PGRP is an antibacterial neutrophil protein. We report that human PGRP-L is a Zn2+-dependent N-acetylmuramoyl-l-alanine amidase (EC 3.5.1.28), an enzyme that hydrolyzes the amide bond between MurNAc and l-Ala of bacterial PGN. The minimum PGN fragment hydrolyzed by PGRP-L is MurNAc-tripeptide. PGRP-L has no direct bacteriolytic activity. The other members of the human PGRP family, PGRP-Ialpha, PGRP-Ibeta, and PGRP-S, do not have the amidase activity. The C-terminal region of PGRP-L, homologous to bacteriophage and bacterial amidases, is required and sufficient for the amidase activity of PGRP-L, although its activity (in the N-terminal delta1-343 deletion mutant) is reduced. The Zn2+ binding amino acids (conserved in PGRP-L and T7 amidase) and Cys-419 (not conserved in T7 amidase) are required for the amidase activity of PGRP-L, whereas three other amino acids, needed for the activity of T7 amidase, are not required for the activity of PGRP-L. These amino acids, although required, are not sufficient for the amidase activity, because changing them to the "active" configuration does not convert PGRP-S into an active amidase. In conclusion, human PGRP-L is an N-acetylmuramoyl-l-alanine amidase and this function is conserved in prokaryotes, insects, and mammals.
Links	PubMed Online version:10.1074/jbc.M307758200
Keywords	Amino Acid Sequence; Animals; Base Sequence; COS Cells; Carbohydrate Sequence; Carrier Proteins/chemistry; Carrier Proteins/metabolism; DNA Primers; Humans; Molecular Sequence Data; N-Acetylmuramoyl-L-alanine Amidase/metabolism; Sequence Homology, Amino Acid; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Zinc/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
HUMAN:PGRP2		GO:0008745: N-acetylmuramoyl-L-alanine amidase activity	ECO:0000314:		F		Fig. 2. PGRP-L is an N-acetylmuramoyl-l-alanine amidase that digests polymeric PGN and synthetic MurNAc-tripeptide.	complete CACAO 12147
HUMAN:PGRP2		GO:0008745: N-acetylmuramoyl-L-alanine amidase activity	ECO:0000247:	UniProtKB:D1LVD8	F		Figure 3 shows that the amino acid sequence of PGRP2 shared some homologies with the bacteriophage T7 lysozyme, which is a member of a family of bacteriophage and bacterial type 2 N-acetylmuramoyl-L-alanine amidases.	complete CACAO 12174

References

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