Sentrin-specific protease 1 is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
that in humans is encoded by the ''SENP1''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
General
So far there are six SUMO
proteases
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the for ...
in humans that have been designated SENP1-3 and SENP5-7 (sentrin/SUMO-specific protease).1 The six proteases possess a conserved
C-terminal
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...
domain which are variable in size, and with a distinct
N-terminal
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...
domain between them. The C-terminal domain shows
catalytic activity and N-terminal domain regulates cell localization and substrate specificity.
Features
SENP1 (Sentrin-specific protease 1) is a human protease of 643 amino acids with a weight of 73 kDa,
EC number in humans 3.4.22.B70, which adopts a conformation that identifies it as a member of the superfamily of cysteine proteases contain a catalytic triad with characterized three amino acids: a
cysteine
Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile.
When present as a deprotonated catalytic residue, sometime ...
at position 603, a
histidine
Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the de ...
at position 533 and
aspartic acid
Aspartic acid (symbol Asp or D; the ionic form is known as aspartate), is an α-amino acid that is used in the biosynthesis of proteins. Like all other amino acids, it contains an amino group and a carboxylic acid. Its α-amino group is in the pro ...
at position 550.
The important nucleophile is cysteine located at the N-terminal
alpha helix
The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues e ...
of the protein core, the other two amino acids, aspartate and histidine, are located in a
beta sheet
The beta sheet, (β-sheet) (also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a g ...
end.
Location
Both SENP1 are located in the
nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
*Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucle ...
and
cytosol
The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells (intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondri ...
depending on the cell type, although it has been seen that is exported out from the nucleus to the cytosol through a sequence of nuclear export (NES) that is located at the C-terminus. The mammalian SENP1 is localized mainly in the nucleus.
Function
SENP1 catalyzes maturation
SUMO protein (small ubiquitin-related modifier), which causes hydrolysis peptide bond of SUMO is in a conserved sequence Gly-Gly-, -Ala-Thr-Tyr at the C-terminal to be added to the conjugation of other proteins (
sumoylation
In molecular biology, SUMO (Small Ubiquitin-like Modifier) proteins are a family of small proteins that are covalently attached to and detached from other proteins in cells to modify their function. This process is called SUMOylation (sometimes w ...
).
In vertebrates there are three members of the family of SUMO: SUMO-1, -2 and -3. SENP1 can catalyze any of these three.
This conjugation of SUMO toward other proteins is a lot like ubiquitination, however these modifications leads to different results depending on the type of protein been modified.
References
Further reading
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External links
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{{PDB Gallery, geneid=29843