The prognosis and investigation of α-defensin-1 (HNP-1) influence on morphological changes of Staphylococcus aureus cells by the atomic-force microscopy data

Abstract

Methods of computer chemistry were used to model the spatial structures of a-defensin-1 (human neutrophil peptide-1, HNP-1) and peptidoglycan molecules. Geometric optimization has been carried out, quantum-chemical characteristics and charge density distribution of the molecules have been studied, molecular docking has been carried out. Using high-resolution atomic-force microscopy, the influence of HNP-1 on the character of morphological changes in the cell wall of gram-positive microorganisms (Staphylococcus aureus) was studied. A pronounced difference in the morphological features of bacterial populations is shown by the nature of the response to the action of HNP-1. Positively charged sites of HNP-1, binding to the negatively charged lipopolysaccharides (LPS) of the outer bacterial membrane, either create cracks in the LPS layer, or bind to sites in LPs that are responsible for interaction with the Ca2+ and Mg2+, cations necessary for stabilizing the cell surface