Endogenous antimicrobial peptides in human colostrum: a peptidomics study by liquid-chromatography high-resolution mass-spectrometry (LC-HRMS) and bioinformatics

Human colostrum is recognized as a source of bioactive compounds that impact on neonatal development, such as antimicrobial peptides. Antimicrobial peptides (AMPs) present some common characteristics, as they are relatively small (<10 kDa), most of them are positively charged and possess α-helical regions. These molecules can protect the newborn against infectious agents such as bacteria, fungi, and viruses. Using an MS- based proteomic approach combined with the application of bioinformatic tools, 29 peptide sequences from human colostrum were annotated in human colostrum. These peptides are potentially antifungal and were enriched in glutamic acid (E), phenylalanine (F), lysine (K) and tryptophan (W) residues. Among the precursor proteins, two have a known 3D structure and their fragments are located in the protein core. In addition, in silico analyses revealed that AMPs containing regions of α-helix and random structures, and high aliphatic index (mean of 85.29) tend to be thermostable. In this work with human colostrum, previously unreported peptides with potential antimicrobial activity were annotated and structurally characterized via bioinformatic tools.