[Antimicrobial peptide may originate from hemoglobin and play a role in the antibacterial mechanisms of endometrium].

OBJECTIVE: To isolate and purify antimicrobial peptides from human uterus mucus. METHODS: Acid-soluble extract was obtained from the specimens of endometrium mucus from 3 hysteromyomas patients during total hysterectomy. Acidic urea-polyacrylamide gel electrophoresis was used to analyze the acidic extract. The corresponding antimicrobial band HUP was further isolated and purified by electrophoretic elution and reversed-phase high-performance liquid chromatography (RP-HPLC). The antimicrobial activity of the fractions was analyzed by agarose radial diffusion assay. The molecular weight was determined by Tricine-SDS-PAGE. According to the results of the N-terminal sequencing and Mass Spectrometry analysis, the amino acid sequences of the purified molecules were deduced. The deduced amino acid sequence of the antibacterial fragment was further analyzed by ExPASy and OMIGA softwares. RESULTS: An antibacterial peptide named HUP-39 was purified from the human uterine mucus with a molecular weight of 6.777 Ku. N-terminal sequencing and Mass Spectrometry analysis suggested that this antimicrobial peptide should be hHEM-alpha 33-95 amino acid fragment. ExPASy and OMIGA analysis showed that it contained 3alpha-helical transmembrane domains and its pI was 8.38. The fragment was mainly against Escherichia coli ML-35p, E. coli ATCC 25 922, and the clinically isolated strain E. coli 54 080. CONCLUSION: An antimicrobial peptide has been isolated and purified from human uterine mucus, a hHEM-alpha 33-95 amino acid fragment. The antimicrobial molecule in the uterine mucus originates not only from epithelial cells and leucocytes, but also from erythrocytes.