Antibiotic resistance and need for novel antibiotics have seen focus on antimicrobial peptides (AMPs) increase in recent years. The study investigated purification and de novo characterization of an AMP compound produced by bioactive Geotrichum candidum OMON-1. Antimicrobial extract of G. candidum OMON-1 was purified via reverse-phase high-performance liquid chromatography (RP-HPLC). Purified compound (GP-2B) was characterized on liquid chromatography–mass spectrometry (LC–MS) and MALDI-TOF tandem mass spectrometry (MS/MS), and spectra were interpreted using de novo peptide sequencing protocols. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of GP-2B were determined in vitro against Gram-positive clinical isolates and time-kill kinetics against Staphylococcus aureus investigated, while antimicrobial activity was also observed on scanning electron microscope (SEM). GP-2B was successfully purified on RP-HPLC with trifluoroacetic acid-buffered acetonitrile. LC–MS confirmed GP-2B as pure and positively charged with molecular mass 409.23 amu, while characterization of MS/MS spectrum via de novo peptide sequencing described it a tripeptide with carboxymethylcystyl–asparagyl–aspartate amino acid sequence. GP-2B had MIC 8 and 32 µg/mL against antibiotic-sensitive and -resistant S. aureus, respectively, and 64 µg/mL for Enterococci strains. MBC was fourfold MIC, while GP-2B reduced S. aureus by 21.8% and 30% at 5× and 10× MIC, respectively, in time-kill kinetics. SEM images also confirmed bacteriostasis of S. aureus cells. This study successfully purified and characterized via de novo sequencing, a novel bacteriostatic AMP from G. candidum OMON-1.

近年来，抗生素耐药性和对新型抗生素的需求已集中在抗菌肽（AMP）上。该研究调查了由具有生物活性的念珠菌OMON-1产生的AMP化合物的纯化和从头表征。的抗微生物提取物白地OMON-1通过反相高效液相色谱法（RP-HPLC）进行纯化。纯化的化合物（GP-2B）在液相色谱-质谱（LC-MS）和MALDI-TOF串联质谱（MS / MS）上进行了表征，并使用从头肽测序方案对光谱进行了解释。在体外确定GP-2B对革兰氏阳性临床分离株的最小抑菌浓度（MIC）和最小杀菌浓度（MBC），对GP-2B的时间杀灭动力学对金黄色葡萄球菌进行了研究，同时在扫描电子显微镜（SEM）上也观察到了抗菌活性。GP-2B用三氟乙酸缓冲的乙腈在RP-HPLC上成功纯化。LC-MS证实GP-2B纯净，带正电荷，分子质量为409.23 amu，而通过从头肽测序对MS / MS谱图进行的表征描述它是具有羧甲基胱氨酰-天冬酰胺基-天冬氨酸氨基酸序列的三肽。GP-2B对抗生素敏感和耐药的金黄色葡萄球菌的MIC分别为8和32 µg / mL，对肠球菌菌株的MIC为64 µg / mL 。MBC是MIC的四倍，而GP-2B减少了金黄色葡萄球菌在5倍和10倍MIC下的时间杀灭动力学分别为21.8％和30％。SEM图像也证实了金黄色葡萄球菌细胞的抑菌作用。这项研究通过从头测序获得了成功的纯化，并从头测序，这是一种来自假丝酵母OMON-1的新型抑菌AMP 。