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Difference between revisions of "Glycoside Hydrolase Family 104"
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[[Image:LTreaction.jpg|thumb|right|'''Figure 1.''' Reaction catalyzed by family GH104 enzymes. LT, lytic transglycosylase. (''click to enlarge'').]]The glycoside hydrolases of this family are lytic transglyosylases (also referred to as peptidoglycan lyases) of bacteriophage origin and they constitute family 4 of the classification scheme of Blackburn and Clarke <cite>1</cite>. The prototype for this family is the enzyme from ''lambda'' phage. | [[Image:LTreaction.jpg|thumb|right|'''Figure 1.''' Reaction catalyzed by family GH104 enzymes. LT, lytic transglycosylase. (''click to enlarge'').]]The glycoside hydrolases of this family are lytic transglyosylases (also referred to as peptidoglycan lyases) of bacteriophage origin and they constitute family 4 of the classification scheme of Blackburn and Clarke <cite>1</cite>. The prototype for this family is the enzyme from ''lambda'' phage. | ||
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== Catalytic Residues == | == Catalytic Residues == | ||
| − | + | As with other lytic transglycosylases (families [[GH23]], [[GH102]], and [[GH103]]), the GH104 enzymes are thought to possess a single catalytic acid/base residue. This residue in ''lambda'' phage lytic transglycosylase has been inferred by X-ray crystallography as Glu19 <cite>3</cite>. The mechanism of action of the family GH104 enzymes has not been investigated and thus it is not known if they follow that of the lytic transglycosylases of families [[GH23]], [[GH102]], or [[GH103]]. | |
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== Family Firsts == | == Family Firsts == | ||
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== References == | == References == | ||
Revision as of 20:56, 20 February 2010
This page is currently under construction. This means that the Responsible Curator has deemed that the page's content is not quite up to CAZypedia's standards for full public consumption. All information should be considered to be under revision and may be subject to major changes.
- Author: ^^^Anthony Clarke^^^
- Responsible Curator: ^^^Anthony Clarke^^^
| Glycoside Hydrolase Family GHnn | |
| Clan | none |
| Mechanism | retaining |
| Active site residues | known |
| CAZy DB link | |
| http://www.cazy.org/fam/GHnn.html | |
The glycoside hydrolases of this family are lytic transglyosylases (also referred to as peptidoglycan lyases) of bacteriophage origin and they constitute family 4 of the classification scheme of Blackburn and Clarke [1]. The prototype for this family is the enzyme from lambda phage.
These enzymes cleave the β-1,4 linkage between N-acetylmuramoyl and N-acetylglucosaminyl residues in peptidoglycan (Figure 1). No other activities have been observed.
Kinetics and Mechanism
The lytic transglycosidases, strictly speaking, are retaining enzymes. However, they are not hydrolases but rather catalyse an intramolecular glycosyl transferase reaction onto the C-6 hydroxyl group of the muramoyl residue leading to the generation of a terminal 1,6-anhdyromuramoyl product (Figure 1) thus lacking a reducing end [2]. No detailed analyses involving either steady state or pre-steady state kinetic studies have been reported.
Catalytic Residues
As with other lytic transglycosylases (families GH23, GH102, and GH103), the GH104 enzymes are thought to possess a single catalytic acid/base residue. This residue in lambda phage lytic transglycosylase has been inferred by X-ray crystallography as Glu19 [3]. The mechanism of action of the family GH104 enzymes has not been investigated and thus it is not known if they follow that of the lytic transglycosylases of families GH23, GH102, or GH103.
Three-dimensional structures
The three-dimensional structure of only the lambda phage enzyme has been solved [4], and like the other lytic transglycosylases of families GH23, and GH103, it possesses the well characterized α+β “lysozyme fold.”
Family Firsts
References
- Blackburn NT and Clarke AJ. (2001). Identification of four families of peptidoglycan lytic transglycosylases. J Mol Evol. 2001;52(1):78-84. DOI:10.1007/s002390010136 |
- Höltje JV, Mirelman D, Sharon N, and Schwarz U. (1975). Novel type of murein transglycosylase in Escherichia coli. J Bacteriol. 1975;124(3):1067-76. DOI:10.1128/jb.124.3.1067-1076.1975 |
- Leung AK, Duewel HS, Honek JF, and Berghuis AM. (2001). Crystal structure of the lytic transglycosylase from bacteriophage lambda in complex with hexa-N-acetylchitohexaose. Biochemistry. 2001;40(19):5665-73. DOI:10.1021/bi0028035 |