| Accession | ARO:3001302 |
| CARD Short Name | chrB |
| Definition | ChrB is a methyltransferase found in Streptomyces bikiniensis and confers resistance to chalcomycin, mycinamicin, and tylosin. Specifically, this enzyme adds a methyl group to guanosine 748 (E. coli numbering). chrB is found in the chalcomycin biosynthetic cluster and is responsible for self-resistance in S. bikiniensis. |
| AMR Gene Family | non-erm 23S ribosomal RNA methyltransferase (G748) |
| Drug Class | lincosamide antibiotic, macrolide antibiotic |
| Resistance Mechanism | antibiotic target alteration |
| Classification | 11 ontology terms | Show + process or component of antibiotic biology or chemistry + mechanism of antibiotic resistance + determinant of antibiotic resistance + antibiotic target alteration [Resistance Mechanism] + antibiotic target modifying enzyme + ribosomal alteration conferring antibiotic resistance + rRNA methyltransferase conferring antibiotic resistance + antibiotic molecule + 23S ribosomal RNA methyltransferase + lincosamide antibiotic [Drug Class] + macrolide antibiotic [Drug Class] |
| Parent Term(s) | 5 ontology terms | Show + confers_resistance_to_antibiotic tylosin [Antibiotic] + gene involved in self-resistance to antibiotic + confers_resistance_to_antibiotic chalcomycin [Antibiotic] + confers_resistance_to_antibiotic mycinamicin [Antibiotic] + non-erm 23S ribosomal RNA methyltransferase (G748) [AMR Gene Family] |
| Publications | Ward SL, et al. 2004. Antimicrob Agents Chemother 48(12): 4703-4712. Chalcomycin biosynthesis gene cluster from Streptomyces bikiniensis: novel features of an unusual ketolide produced through expression of the chm polyketide synthase in Streptomyces fradiae. (PMID 15561847) |
Prevalence of chrB among the sequenced genomes, plasmids, and whole-genome shotgun assemblies available at NCBI or IslandViewer for 413 important pathogens (see methodological details and complete list of analyzed pathogens). Values reflect percentage of genomes, plasmids, genome islands, or whole-genome shotgun assemblies that have at least one hit to the AMR detection model. Default view includes percentages calculated based on Perfect plus Strict RGI hits. Select the checkbox to view percentages based on only Perfect matches to AMR reference sequences curated in CARD (note: this excludes resistance via mutation as references in protein variant models are often wild-type, sensitive sequences).
| Species | NCBI Chromosome | NCBI Plasmid | NCBI WGS | NCBI GI |
|---|---|---|---|---|
| No prevalence data | ||||
Model Type: protein homolog model
Model Definition: Protein Homolog Models (PHM) detect protein sequences based on their similarity to a curated reference sequence, using curated BLASTP bitscore cut-offs. Protein Homolog Models apply to all genes that confer resistance through their presence in an organism, such as the presence of a beta-lactamase gene on a plasmid. PHMs include a reference sequence and a bitscore cut-off for detection using BLASTP. A Perfect RGI match is 100% identical to the reference protein sequence along its entire length, a Strict RGI match is not identical but the bit-score of the matched sequence is greater than the curated BLASTP bit-score cutoff, Loose RGI matches have a bit-score less than the curated BLASTP bit-score cut-off.
Bit-score Cut-off (blastP): 500