Discovery and characterization of arsenic-containing RiPPs: a novel antibiotic family against multidrug resistance
Disciplines
Amino Acids, Peptides, and Proteins | Bacteriology | Biochemistry | Environmental Microbiology and Microbial Ecology | Integrative Biology | Molecular Biology | Organic Chemicals
Abstract (300 words maximum)
Alarming rise of antimicrobial resistance threatens global public health, calling for discovery of new antibiotics with novel chemical scaffolds and mechanisms of action. Although arsenic is traditionally viewed as a toxic compound, history demonstrates its therapeutic potential—from its use in traditional Chinese medicine, to Paul Ehrlich’s Salvarsan for syphilis, and, more recently, the arsenic trioxide in leukemia treatment. Arsinothricin (AST), recently discovered organoarsenical antibiotic, exhibits potent antimicrobial activity against various pathogenic bacteria and even protozoan parasites with minimal cytotoxicity, further highlighting promises of arsenic-based compounds as antimicrobials. Our objective is to build on this foundation and discover further arsenic-containing antibiotics. To this end, genome mining was employed using the AST biosynthetic gene arsM as a molecular probe, and a novel biosynthetic gene cluster (BGC) were identified in Microbispora rosea strain. In addition to arsM, the BGC contains a gene for SPASM domain radical S-adenosyl methionine (rSAM) enzyme, which is often involved in biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), along with a putative gene for a precursor peptide. RiPPs are known for diverse bioactivities, including antimicrobial activity. The gene composition, therefore, strongly suggests that the BGC encodes a RiPP that uniquely contains methylated arsenical, and we name the prospective product an arsenic-containing RiPP (AsRiPP). When cultured with arsenite, M. rosea produced an organic arsenic species. The organic arsenic species crudely purified from a large culture exhibited antibiotic activity, supporting our hypothesis that the strain produces an arsenic-containing antibiotic, presumably the AsRiPP. In parallel, Escherichia coli cells expressing genes from the M. rosea BGC, either solely or in various combinations, were constructed. These constructs are being used to elucidate AsRiPP biosynthetic pathway. These approaches will be continued to clarify the association of the AsRiPP’s BGCs and the discovered organic arsenic species.
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Academic department under which the project should be listed
CSM – Molecular and Cellular Biology
Primary Investigator (PI) Name
Masafumi Yoshinaga
Additional Faculty
Mohammad Abdul Halim, CSM - Chemistry and Biochemistry, mhalim1@kennesaw.edu
Discovery and characterization of arsenic-containing RiPPs: a novel antibiotic family against multidrug resistance
Alarming rise of antimicrobial resistance threatens global public health, calling for discovery of new antibiotics with novel chemical scaffolds and mechanisms of action. Although arsenic is traditionally viewed as a toxic compound, history demonstrates its therapeutic potential—from its use in traditional Chinese medicine, to Paul Ehrlich’s Salvarsan for syphilis, and, more recently, the arsenic trioxide in leukemia treatment. Arsinothricin (AST), recently discovered organoarsenical antibiotic, exhibits potent antimicrobial activity against various pathogenic bacteria and even protozoan parasites with minimal cytotoxicity, further highlighting promises of arsenic-based compounds as antimicrobials. Our objective is to build on this foundation and discover further arsenic-containing antibiotics. To this end, genome mining was employed using the AST biosynthetic gene arsM as a molecular probe, and a novel biosynthetic gene cluster (BGC) were identified in Microbispora rosea strain. In addition to arsM, the BGC contains a gene for SPASM domain radical S-adenosyl methionine (rSAM) enzyme, which is often involved in biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), along with a putative gene for a precursor peptide. RiPPs are known for diverse bioactivities, including antimicrobial activity. The gene composition, therefore, strongly suggests that the BGC encodes a RiPP that uniquely contains methylated arsenical, and we name the prospective product an arsenic-containing RiPP (AsRiPP). When cultured with arsenite, M. rosea produced an organic arsenic species. The organic arsenic species crudely purified from a large culture exhibited antibiotic activity, supporting our hypothesis that the strain produces an arsenic-containing antibiotic, presumably the AsRiPP. In parallel, Escherichia coli cells expressing genes from the M. rosea BGC, either solely or in various combinations, were constructed. These constructs are being used to elucidate AsRiPP biosynthetic pathway. These approaches will be continued to clarify the association of the AsRiPP’s BGCs and the discovered organic arsenic species.