Glycoside hydrolase family 67
Encyclopedia
In molecular biology, glycoside hydrolase family 67 is a family
of glycoside hydrolases
.
Glycoside hydrolases are a widespread group of enzymes that hydrolyse the glycosidic bond
between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families. This classification is available on the CAZy(http://www.cazy.org/GH1.html) web site, and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.
Glycoside hydrolase family 67 includes alpha-glucuronidases
, these are components of an ensemble of enzyme
s central to the recycling of photosynthetic biomass
, remove the alpha-1,2 linked 4-O-methyl glucuronic acid
from xylans
.
Members of this family consist of three structural domains. Deletion mutants of alpha-glucuronidase from Bacillus stearothermophilus
have indicated that the central region is responsible for the catalytic activity. Within this central domain, the invariant Glu
and Asp
(residues 391 and 364 respectively from Bacillus stearothermophilus
) are thought to from the catalytic centre. The C-terminal region of alpha-glucuronidase is mainly alpha-helical
. It wraps around the catalytic domain, making additional interactions both with the N-terminal domain of its parent monomer
and also forming the majority of the dimer-surface with the equivalent C-terminal domain of the other monomer of the dimer
.
Protein family
A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....
of glycoside hydrolases
Glycoside hydrolase
Glycoside hydrolases catalyze the hydrolysis of the glycosidic linkage to release smaller sugars...
.
Glycoside hydrolases are a widespread group of enzymes that hydrolyse the glycosidic bond
Glycosidic bond
In chemistry, a glycosidic bond is a type of covalent bond that joins a carbohydrate molecule to another group, which may or may not be another carbohydrate....
between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families. This classification is available on the CAZy(http://www.cazy.org/GH1.html) web site, and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.
Glycoside hydrolase family 67 includes alpha-glucuronidases
Alpha-glucuronidase
For beta-glucuronidase, see Beta-glucuronidaseIn enzymology, an alpha-glucuronidase is an enzyme that catalyzes the chemical reactionThus, the two substrates of this enzyme are alpha-D-glucuronoside and H2O, whereas its two products are alcohol and D-glucuronate.This enzyme belongs to the family...
, these are components of an ensemble of enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
s central to the recycling of photosynthetic biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
, remove the alpha-1,2 linked 4-O-methyl glucuronic acid
Glucuronic acid
Glucuronic acid is a carboxylic acid. Its structure is similar to that of glucose. However, glucuronic acid's sixth carbon is oxidized to a carboxylic acid...
from xylans
Xylan
Xylan is a generic term used to describe a wide variety of highly complex polysaccharides that are found in plant cell walls and some algae. Xylans are polysaccharides made from units of xylose ....
.
Members of this family consist of three structural domains. Deletion mutants of alpha-glucuronidase from Bacillus stearothermophilus
Bacillus stearothermophilus
Bacillus stearothermophilus is a rod-shaped, Gram-positive bacterium and a member of the division Firmicutes. The bacteria is a thermophile and is widely distributed in soil, hot springs, ocean sediment, and is a cause of spoilage in food products. It will grow within a temperature range of 30-75...
have indicated that the central region is responsible for the catalytic activity. Within this central domain, the invariant Glu
Glutamic acid
Glutamic acid is one of the 20 proteinogenic amino acids, and its codons are GAA and GAG. It is a non-essential amino acid. The carboxylate anions and salts of glutamic acid are known as glutamates...
and Asp
Aspartic acid
Aspartic acid is an α-amino acid with the chemical formula HOOCCHCH2COOH. The carboxylate anion, salt, or ester of aspartic acid is known as aspartate. The L-isomer of aspartate is one of the 20 proteinogenic amino acids, i.e., the building blocks of proteins...
(residues 391 and 364 respectively from Bacillus stearothermophilus
Bacillus stearothermophilus
Bacillus stearothermophilus is a rod-shaped, Gram-positive bacterium and a member of the division Firmicutes. The bacteria is a thermophile and is widely distributed in soil, hot springs, ocean sediment, and is a cause of spoilage in food products. It will grow within a temperature range of 30-75...
) are thought to from the catalytic centre. The C-terminal region of alpha-glucuronidase is mainly alpha-helical
Alpha helix
A common motif in the secondary structure of proteins, the alpha helix is a right-handed coiled or spiral conformation, in which every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid four residues earlier...
. It wraps around the catalytic domain, making additional interactions both with the N-terminal domain of its parent monomer
Monomer
A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
and also forming the majority of the dimer-surface with the equivalent C-terminal domain of the other monomer of the dimer
Protein dimer
In biochemistry, a dimer is a macromolecular complex formed by two, usually non-covalently bound, macromolecules like proteins or nucleic acids...
.