Albomycins are a group of naturally occurring antibiotics belonging to the class of sideromycins, which are "compounds composed of iron carriers called

siderophore Siderophores (Greek: "iron carrier") are small, high-affinity iron- chelating compounds that are secreted by microorganisms such as bacteria and fungi. They help the organism accumulate iron. Although a widening range of siderophore functions is n ...

s linked to

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy, ...

moieties". They are particularly effective against

Gram-negative bacteria Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

of the family ''

Enterobacteriaceae Enterobacteriaceae is a large family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject of debate, but on ...

'' and few

Gram-positive bacteria In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bact ...

such s ''

Streptococcus pneumoniae ''Streptococcus pneumoniae'', or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic (under aerobic conditions) or beta-hemolytic (under anaerobic conditions), aerotolerant anaerobic member of the genus Streptococcus. They a ...

'', ''

Bacillus subtilis ''Bacillus subtilis'', known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus '' Baci ...

'' and ''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...

''. In 2000 a group of scientists from SmithKline Beecham Pharmaceuticals, UK reported that the antibiotic part of albomycin ''in vitro'' can inhibit seryl t-RNA synthetase from both eukaryotic and prokaryotic representatives.

Structure

Albomycins are naturally occurring sideromycins produced by some streptomycetes. The siderophore part of albomycin δ2 is similar to

ferrichrome Ferrichrome is a cyclic hexa-peptide that forms a complex with iron atoms. It is a siderophore composed of three glycine and three modified ornithine residues with hydroxamate groups N(OH)C(=O)C- The 6 oxygen atoms from the three hydroxamate gr ...

. It contains three molecules of δ-N-hydroxy-δ-N-acetyl

ornithine Ornithine is a non-proteinogenic amino acid that plays a role in the urea cycle. Ornithine is abnormally accumulated in the body in ornithine transcarbamylase deficiency. The radical is ornithyl. Role in urea cycle L-Ornithine is one of the prod ...

linked to a

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 − for ...

, all by peptide linkage. The C-terminus of the

is linked to another

attached to the antibiotically active 4’-thio (N4-carbamoyl-3-methyl)

cytidine Cytidine (symbol C or Cyd) is a nucleoside molecule that is formed when cytosine is attached to a ribose ring (also known as a ribofuranose) via a β-N1-glycosidic bond. Cytidine is a component of RNA. It is a white water-soluble solid. which is ...

moiety. The trihydroxamate part serves the

function as it can trap Fe⁺³ and is essential for active transport of the antibiotic. Iron-free albomycin δ2 has a molecular weight of 992 Da, and when loaded with iron it is 1045 Da.

References

{{reflist Antibiotics Siderophores