YcaO is a protein found in bacteria which is involved in the synthesis of thiazole/oxazole modified

microcin Microcins are very small bacteriocins, composed of relatively few amino acids. For this reason, they are distinct from their larger protein cousins. The classic example is microcin V, of ''Escherichia coli''. Subtilosin A is another bacterioci ...

antibiotics, such as

bottromycin Bottromycin is a macrocyclic peptide with antibiotic activity. It was first discovered in 1957 as a natural product isolated from ''Streptomyces bottropensis''. It has been shown to inhibit methicillin-resistant ''Staphylococcus aureus'' (MRSA) and ...

. YcaO performs ATP dependent cyclodehydration to form the

oxazole Oxazole is the parent compound for a vast class of heterocyclic compound, heterocyclic aromatic organic compounds. These are azoles with an oxygen and a nitrogen separated by one carbon. Oxazoles are aromatic compounds but less so than the thiaz ...

and

thiazole Thiazole (), or 1,3-thiazole, is a 5-membered heterocyclic compound that contains both sulfur and nitrogen. The term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the ...

moieties of the microcin. The YcaO name origin is from a gene naming rubric that was established from the bacterium

Escherichia coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...

. If a gene has an unknown function, it was given a four-letter name starting with the letter Y and the next three letters are given based on the genomic location.

Methyl coenzyme M reductase In enzymology, coenzyme-B sulfoethylthiotransferase, also known as methyl-coenzyme M reductase (MCR) or most systematically as 2-(methylthio)ethanesulfonate:N-(7-thioheptanoyl)-3-O-phosphothreonine S-(2-sulfoethyl)thiotransferase is an enzyme that ...

(MCR) or

Coenzyme-B sulfoethylthiotransferase In enzymology, coenzyme-B sulfoethylthiotransferase, also known as methyl-coenzyme M reductase (MCR) or most systematically as 2-(methylthio)ethanesulfonate:N-(7-thioheptanoyl)-3-O-phosphothreonine S-(2-sulfoethyl)thiotransferase is an enzyme that ...

is a protein known in thioamidation (a posttranslational modification). A Ycao enzyme dependent on ATP is needed for MCR thioamidation as well as a sulfide source. YcaO enzymes are needed to catalyze the ATP-dependent backbone cyclodehydration of polar amino acids such as

Cysteine Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the chemical formula, formula . The thiol side chain in cysteine enables the formation of Disulfide, disulfide bonds, and often participates in enzymatic reactions as ...

Serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − ...

, and

Threonine Threonine (symbol Thr or T) is an amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form when dissolved in water), a carboxyl group (which is in the deprotonated −COO− ...

to the correct thiazoline and (methyl) oxazoline

Heterocycle A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, proper ...

. The side chains of these amino acids can act as

Nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...

s. The

Thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl grou ...

group in cysteine and the hydroxyl group of serine and threonine are strong nucleophiles.

References

Protein domains {{Biochem-stub