Information about Protein Subunit
In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles (or "coassembles") with other protein molecules to form a multimeric or oligomeric protein. Many naturally-occurring proteins and enzymes are multimeric. Examples include hemoglobin, ion channels, DNA polymerase, nucleosomes and microtubules. The subunits of a multimeric protein may be identical, homologous or totally dissimilar and dedicated to disparate tasks. In some protein assemblies, one subunit may be referred to as a "regulatory subunit" and another as a "catalytic subunit." An enzyme composed of both regulatory and catalytic subunits when assembled is often referred to as a holoenzyme.
One subunit is made of one polypeptide chain. A polypeptide chain have one gene coding for it - meaning that a protein must have one gene for each subunit.
A subunit is often named with a Greek or Roman letter, and the numbers of this type of subunit in a protein is indicated by a subscript. For example, ATP synthase has a type of subunit called α. Three of these are present in the ATP synthase molecule, and is therefore designated α3. Larger groups of subunits can also the specified, like α3β3-hexamer and c-ring.
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A subunit is often named with a Greek or Roman letter, and the numbers of this type of subunit in a protein is indicated by a subscript. For example, ATP synthase has a type of subunit called α. Three of these are present in the ATP synthase molecule, and is therefore designated α3. Larger groups of subunits can also the specified, like α3β3-hexamer and c-ring.
See also
Structural biology is a branch of molecular biology concerned with the study of the architecture and shape of biological macromolecules—proteins and nucleic acids in particular—and what causes them to have the structures they have.
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Proteins are large organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues.
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molecule is defined as a sufficiently stable electrically neutral group of at least two atoms in a definite arrangement held together by strong chemical bonds.[1][2] In organic chemistry and biochemistry, the term molecule
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Enzymes are proteins that catalyze (i.e. accelerate) chemical reactions.[1] In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, the products.
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Hemoglobin, also spelled haemoglobin and abbreviated Hb, is the iron-containing oxygen-transport metalloprotein in the red blood cells of the blood in vertebrates and other animals.
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Ion channels are pore-forming proteins that help to establish and control the small voltage gradient across the plasma membrane of all living cells (see cell potential) by allowing the flow of ions down their electrochemical gradient.
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Pol I: implicated in DNA repair; has both 5'->3'(Nick translation) and 3'->5' (Proofreading) exonuclease activity. Pol II: involved in replication of damaged DNA; has both 5'->3'chain extension ability and 3'->5' exonuclease activity.
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Nucleosomes are the fundamental repeating subunits of all eukaryotic chromatin (except when packaged in sperm). They package DNA into chromosomes inside the cell nucleus and control gene expression.
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Microtubules are one of the components of the cytoskeleton. They have diameter of ~ 24 nm and length varying from several micrometers to possibly millimeters in axons of nerve cells.
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In evolutionary biology, homology is any similarity between characters that is due to their shared ancestry. There are examples in different branches of biology. Anatomical structures that perform the same function in different biological species and evolved from the same structure
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Peptides (from the Greek πεπτίδια, "small digestibles") are short polymers formed from the linking, in a defined order, of α-amino acids.
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For a non-technical introduction to the topic, see .
A gene is a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with regulatory regions, transcribed regions and/or other functional sequence regions...... Click the link for more information.
ATP synthase (EC 3.6.3.14 ) is a general term for an enzyme that can synthesize adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and inorganic phosphate by utilizing some form of energy.
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In biochemistry, quaternary structure is the arrangement of multiple folded protein molecules in a multi-subunit complex.
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Description and examples
Many proteins are actually assemblies of more than one polypeptide chain, which in the context of the larger assemblage are..... Click the link for more information.
In biochemistry, allosteric regulation is the regulation of an enzyme or protein by binding an effector molecule at the protein's allosteric site (that is, a site other than the protein's active site).
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In biochemistry, a macromolecule exhibits cooperative binding if its affinity for its ligand changes with the amount of ligand already bound.
Cooperative binding is a special case of allostery.
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Cooperative binding is a special case of allostery.
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