Glycoside hydrolase family 89
Encyclopedia
In molecular biology, glycoside hydrolase family 89 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 89 CAZY GH_89 includes enzymes with α-N-acetylglucosaminidase
activity. The enzyme consist of three structural
domains, the N-terminal domain has an alpha
-beta fold, the central domain has a TIM barrel
fold, and the C-terminal domain has an all alpha helical fold.
Alpha-N-acetylglucosaminidase is a lysosomal
enzyme
required for the stepwise degradation of heparan sulphate. Mutations on the alpha-N-acetylglucosaminidase (NAGLU
) gene
can lead to Mucopolysaccharidosis
type IIIB (MPS IIIB; or Sanfilippo syndrome
type B) characterised by neurological dysfunction but relatively mild somatic
manifestations.
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 89 CAZY GH_89 includes enzymes with α-N-acetylglucosaminidase
Alpha-N-acetylglucosaminidase
Alpha-N-acetylglucosaminidase is a protein associated with Sanfilippo syndrome....
activity. The enzyme consist of three structural
Protein structure
Proteins are an important class of biological macromolecules present in all organisms. Proteins are polymers of amino acids. Classified by their physical size, proteins are nanoparticles . Each protein polymer – also known as a polypeptide – consists of a sequence formed from 20 possible L-α-amino...
domains, the N-terminal domain has an alpha
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...
-beta fold, the central domain has a TIM barrel
TIM barrel
The TIM barrel is a conserved protein fold consisting of eight α-helices and eight parallel β-strands that alternate along the peptide backbone. The structure is named after triosephosphate isomerase, a conserved glycolytic enzyme. TIM barrels are quite common among the conserved protein folds...
fold, and the C-terminal domain has an all alpha helical fold.
Alpha-N-acetylglucosaminidase is a lysosomal
Lysosome
thumb|350px|Schematic of typical animal cell, showing subcellular components. [[Organelle]]s: [[nucleoli]] [[cell nucleus|nucleus]] [[ribosomes]] [[vesicle |vesicle]] rough [[endoplasmic reticulum]]...
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...
required for the stepwise degradation of heparan sulphate. Mutations on the alpha-N-acetylglucosaminidase (NAGLU
Alpha-N-acetylglucosaminidase
Alpha-N-acetylglucosaminidase is a protein associated with Sanfilippo syndrome....
) gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
can lead to Mucopolysaccharidosis
Mucopolysaccharidosis
Mucopolysaccharidoses are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal enzymes needed to break down molecules called glycosaminoglycans - long chains of sugar carbohydrates in each of our cells that help build bone, cartilage, tendons, corneas, skin and...
type IIIB (MPS IIIB; or Sanfilippo syndrome
Sanfilippo syndrome
Sanfilippo syndrome, or Mucopolysaccharidosis III is a rare autosomal recessive lysosomal storage disease. It is caused by a deficiency in one of the enzymes needed to break down the glycosaminoglycan heparan sulfate .Although undegraded heparan sulfate is the primary stored substrate,...
type B) characterised by neurological dysfunction but relatively mild somatic
Somatic
The term somatic means 'of the body',, relating to the body. In medicine, somatic illness is bodily, not mental, illness. The term is often used in biology to refer to the cells of the body in contrast to the germ line cells which usually give rise to the gametes...
manifestations.