home *** CD-ROM | disk | FTP | other *** search
- ******************************************
- * D-alanine--D-alanine ligase signatures *
- ******************************************
-
- D-alanine--D-alanine ligase (EC 6.3.2.4) is a bacterial enzyme involved in
- cell-wall biosynthesis. It participates in forming UDP-N-acetylmuramyl
- pentapeptide, the peptidoglycan precursor.
-
- In Escherichia coli and related bacteria, there are two different D-ala--D-ala
- ligase isozymes (genes ddlA and ddlB) [1]. In Enterobacterium faecium and
- gallinarum, genes vanA and vanC encode D-ala--D-ala ligases of altered
- specificity, which catalyze ester bond formations between D-ala and various
- D-hydroxy acids [2]. They are required for resistance to glycopeptide
- antibiotics, such as vancomycin which inhibits late stages in cell-wall
- synthesis.
-
- These enzymes are proteins of 300 to 360 amino acids. There are many
- conserved regions, of which we selected two as signature patterns. Both are
- Gly-rich and could be involved in ATP-binding. The first pattern is located
- near the N-terminal extremity, the second in the C-terminal section.
-
- -Consensus pattern: H-G-x(2)-G-E-D-G-x-[LIVMA]-[QS]-G
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: L-G-x(2)-G-x-[AG]-R-[LIVM]-D
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Last update: June 1994 / Patterns and text revised.
-
- [ 1] Zawadzke L.E., Bugg T.D., Walsh C.T.
- Biochemistry 30:1673-1682(1991).
- [ 2] Dutka-Malen S., Molinas C., Arthur M., Courvalin P.
- Gene 112:53-58(1992).
-