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 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 wall ...

of the family '' Enterobacteriaceae'' and few Gram-positive bacteria 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 ar ...

'', ''

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 ''Bacillus ...

'' and '' Staphylococcus aureus''. 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. 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 produ ...

linked to a serine, all by peptide linkage. The C-terminus of the serine is linked to another serine 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 ...

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