Cloning and sequence analysis of genes involved in erythromycin biosynthesis in Saccharopolyspora erythraea: sequence similarities between EryG and a family of S-adenosylmethionine-dependent methyltransferases

Abstract

The gene cluster (ery) responsible for production of the macrolide antibiotic erythromycin by Saccharopolyspora erythraea is also known to contain ermE, the gene conferring resistance to the antibiotic. The nucleotide sequence has been determined of a 4.5 kb portion of the biosynthetic gene cluster, from a region lying between 3.7 kb and 8.2 kb 3' of ermE. This has revealed the presence of four complete open reading frames, including the previously known ery gene eryG, which catalyses the last step in the biosynthetic pathway. Comparison of the amino acid sequence of EryG with the sequence of other S-adenosylmethionine (SAM)-dependent methyltransferases has revealed that one of the sequence motifs previously suggested to be part of the SAM-binding site is present not only in EryG but also in many other recently sequenced SAM-dependent methyltransferases. Previous genetic studies have shown that this region also contains gene(s) involved in hydroxylation of the intermediate 6-deoxyerythronolide B. One of the three other open reading frames (eryF) in fact shows very high sequence similarity to known cytochrome P450 hydroxylases. An adjacent gene (ORF5) shows a strikingly high degree of similarity to prokaryotic and eukaryotic acyltransferases and thioesterases.

Inactivation of gilGT, Encoding a C‐Glycosyltransferase, and gilOIII, Encoding a P450 Enzyme, Allows the Details of the Late Biosynthetic Pathway to Gilvocarcin V to be Delineated

“…By far the greatest homology (42% amino-acid identity) of this protein was found to be with an enzyme from Nocardioides sp., strain KP7 (orf4 gene product), which is presumably involved in phenanthrene degradation. [19] Significant homologies were also observed with EthB (34% amino-acid identity), a cytochrome-P450 monooxygenase from Rhodococcus ruber involved in the degradation of ethyl tert-butyl ether (ETBE), [20] and to a number of bacterial cytochrome-P450 enzymes (> 30% amino-acid identity), including oxygenases of macrolide antibiotic biosyntheses pathways, for example, EryF, [21] TylI, [22] PicK (PikC), [23,24] and OleP. [25] All the latter enzymes catalyze the hydroxylation of aliphatic macro-lide structures.…”

Cloning of a potential cytochrome P450 from the Archaeon Sulfolobus solfataricus

“…[10]), CYP107A1 from Saccharopolyspora erythrea (S. eryth. [11]), and ORF1 from the fas locus in Rhodococcusfascians (Rh. fasc.…”

Computer-assisted identification of a putative methyltransferase domain in NS5 protein of flaviviruses and 2 protein of reovirus

“…First, this is the only region of detectable similarity among methyltransferases that methylate a wide variety of acceptors but all use the same donor of the methyl group, SAM. Second, the sequence and putative conformation of this site clearly resembles those typical of nucleotide-binding sites, making SAM binding its plausible function (Haydock et al, 1991;Wu et al, 1992).…”

“…The signature UU [DE]xGxGxG (hereafter U designates a bulky aliphatic amino acid residue, and x is any residue) is conserved in most but not all SAMutilizing methyltransferases (Ingrosso et al, 1989;Haydock et al, 1991;Wu et al, 1992). Unexpectedly, this signature was detected in NS5 proteins of all flaviviruses.…”