title: Bacterial expression and antibiotic activities of recombinant variants of human β-defensins on pathogenic bacteria and M. tuberculosis.
abstract: Five variants of human β-defensins (HBDs) were expressed in Escherichia coli using two vector systems (pET28a(+) and pQE30) with inducible expression by IPTG. The last vector has not been previously reported as an expression system for HBDs. The recombinant peptides were different in their lengths and overall charge. The HBDs were expressed as soluble or insoluble proteins depending on the expression system used, and the final protein yields ranged from 0.5 to 1.6 mg of peptide/g of wet weight cells, with purities higher than 90%. The recombinant HBDs demonstrated a direct correlation between antimicrobial activity and the number of basic charged residues; that is, their antimicrobial activity was as follows: HBD3-M-HBD2 > HBD3 = HBD3-M = HB2-KLK > HBD2 when assayed against E. coli, Staphylococcus aureus and Pseudomonas aeruginosa. Interestingly, HBD2 had the best antimicrobial activity against the Mycobacterium tuberculosis strain H37Rv (1.5 μM) and the heterologous tandem peptide, HBD3-M-HBD2, had the best minimal inhibitory concentration (MIC) value (2.7 μM) against a multidrug resistance strain (MDR) of M. tuberculosis, demonstrating the feasibility of the use of HBDs against pathogenic M. tuberculosis reported to be resistant to commercial antibiotics.
authors: Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, UNAM, Apartado Postal 510-3, Cuernavaca, Morelos 61500, Mexico.
authors: Ligia
authors: L
authors: Corrales-Garcia
authors: Ernesto
authors: E
authors: Ortiz
authors: Julio
authors: J
authors: Castañeda-Delgado
authors: Bruno
authors: B
authors: Rivas-Santiago
authors: Gerardo
authors: G
authors: Corzo
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000187:drug effects / Q000472:pathogenicity; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000472:pathogenicity; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000472:pathogenicity; D023083:beta-Defensins / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics*
chemical_list: D010455:Peptides; D011994:Recombinant Proteins; D023083:beta-Defensins