The acyl carrier protein (ACP) is a cofactor of both

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...

and

polyketide Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynth ...

biosynthesis machinery. It is one of the most abundant proteins in cells of ''E. coli.'' In both cases, the growing chain is bound to the ACP via a thioester derived from the distal thiol of a 4'-

phosphopantetheine Phosphopantetheine, also known as 4'-phosphopantetheine, is a prosthetic group of several acyl carrier proteins including the acyl carrier proteins (ACP) of fatty acid synthases, ACPs of polyketide synthases, the peptidyl carrier proteins (PCP), ...

moiety.

Structure

The ACPs are small negatively charged α-helical bundle proteins with a high degree of structural and amino acid similarity. The structures of a number of acyl carrier proteins have been solved using various

NMR Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with ...

and crystallography techniques. The ACPs are related in structure and mechanism to the peptidyl carrier proteins (PCP) from

nonribosomal peptide Nonribosomal peptides (NRP) are a class of peptide secondary metabolites, usually produced by microorganisms like bacteria and fungi. Nonribosomal peptides are also found in higher organisms, such as nudibranchs, but are thought to be made by bacter ...

synthases.

Biosynthesis

Subsequent to the expression of the inactive ''apo'' ACP, the 4'-phosphopantetheine moiety is attached to a serine residue. This coupling is mediated by

acyl carrier protein synthase In enzymology and molecular biology, a holo- cyl-carrier-proteinsynthase (ACPS, ) is an enzyme that catalyzes the chemical reaction: :CoA- '-phosphopantetheine+ apo-acyl carrier protein \rightleftharpoons adenosine 3',5'-bisphosphate + holo-acy ...

(ACPS), a 4'-phosphopantetheinyl transferase. 4'-

Phosphopantetheine Phosphopantetheine, also known as 4'-phosphopantetheine, is a prosthetic group of several acyl carrier proteins including the acyl carrier proteins (ACP) of fatty acid synthases, ACPs of polyketide synthases, the peptidyl carrier proteins (PCP), ...

is a prosthetic group of several acyl carrier proteins including the acyl carrier proteins (ACP) of

fatty acid synthase Fatty acid synthase (FAS) is an enzyme that in humans is encoded by the ''FASN'' gene. Fatty acid synthase is a multi-enzyme protein that catalyzes fatty acid synthesis. It is not a single enzyme but a whole enzymatic system composed of two iden ...

s, ACPs of

polyketide synthase Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynth ...

s, the peptidyl carrier proteins (PCP), as well as aryl carrier proteins (ArCP) of

nonribosomal peptide synthetases Nonribosomal peptides (NRP) are a class of peptide secondary metabolites, usually produced by microorganisms like bacteria and fungi. Nonribosomal peptides are also found in higher organisms, such as nudibranchs, but are thought to be made by bacter ...

(NRPS).

References

External links

* {{Carrier proteins Proteins