RESUMO
Defensins confer host defense against microorganisms and are important for human health. Single nucleotide polymorphisms (SNPs) in defensin gene-coding regions could lead to less active variants. Using SNP data available at the dbSNP database and frequency information from the 1000 Genomes Project, two DEFA5 (L26I and R13H) and eight DEFB1 (C35S, K31T, K33R, R29G, V06I, C12Y, Y28* and C05*) missense and nonsense SNPs that are located within mature regions of the coded defensins were retrieved. Such SNPs are rare and population restricted. In order to assess their antibacterial activity against Escherichia coli, two linear regression models were used from a previous work, which models the antibacterial activity as a function of solvation potential energy, using molecular dynamics data. Regarding only the antibacterial predictions, for HD5, no biological differences between wild-type and its variants were observed; while for HBD1, the results suggest that the R29G, K31T, Y28* and C05* variants could be less active than the wild-type one. The data here reported could lead to a substantial improvement in knowledge about the impact of missense SNPs in human defensins and their world distribution. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 633-644, 2016.
Assuntos
Antibacterianos , Escherichia coli/efeitos dos fármacos , Simulação de Dinâmica Molecular , Polimorfismo de Nucleotídeo Único , alfa-Defensinas , beta-Defensinas , Antibacterianos/química , Antibacterianos/farmacologia , Humanos , alfa-Defensinas/química , alfa-Defensinas/genética , alfa-Defensinas/farmacologia , beta-Defensinas/química , beta-Defensinas/genética , beta-Defensinas/farmacologiaRESUMO
The structure-activity relationship of defensins is not clear. It is known that point mutations in HD5 and HBD1 could modify their activities; however, these mutations do not seem to alter their three-dimensional structures. Here, applying molecular dynamics simulations, this relationship was studied in depth. There are modifications in flexibility, solvent accessible surface area and radius of gyration, but these properties are not reflected in the activity. Only alterations in the solvation potential energy were correlated to antibacterial activity against Escherichia coli. Data here reported could lead to a better understanding of structural and functional aspects of α- and ß-defensins.