McAvoy Andrew C, Threatt Paxton H, Kapcia Joseph, Garg Neha
School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States.
Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, California 92697-2525, United States.
ACS Chem Biol. 2023 Apr 21;18(4):711-723. doi: 10.1021/acschembio.2c00529. Epub 2022 Oct 10.
Opportunistic infections by are life threatening for patients suffering from cystic fibrosis and chronic granulomatous disease. These infections are often associated with variable clinical outcomes, prompting an interest in molecular investigations of phenotypes associated with disease severity. The production of the pyomelanin pigment is one such phenotype, which was recently linked to the ability of clinical strains to carry out biotransformation of the antibiotic trimethoprim. However, this biotransformation product was not identified, and differences in metabolite production associated with pyomelanin pigmentation are poorly understood. Here, we identify several key metabolites produced exclusively by the pyomelanin-producing strains. To provide insight into the structures and biosynthetic origin of these metabolites, we developed a mass spectrometry-based strategy coupling unsupervised substructure prediction with stable isotope labeling referred to as MAS-SILAC (Metabolite Annotation assisted by Substructure discovery and Stable Isotope Labeling by Amino acids in Cell culture). This approach led to discovery of homogentisic acid as a precursor for biosynthesis of several natural products and for biotransformation of trimethoprim, representing a previously unknown mechanism of antibiotic tolerance. This work presents application of computational methods for analysis of untargeted metabolomic data to link the chemotype of pathogenic microorganisms with a specific phenotype. The observations made in this study provide insights into the clinical significance of the melanated phenotype.
对于患有囊性纤维化和慢性肉芽肿病的患者来说，[具体病原体]引起的机会性感染会危及生命。这些感染通常与多变的临床结果相关，这促使人们对与疾病严重程度相关的表型进行分子研究。脓性黑色素色素的产生就是这样一种表型，最近它与临床菌株对抗生素甲氧苄啶进行生物转化的能力有关。然而，这种生物转化产物尚未得到鉴定，而且与脓性黑色素色素沉着相关的代谢物产生差异也知之甚少。在这里，我们鉴定了几种仅由产生脓性黑色素的菌株产生的关键代谢物。为了深入了解这些代谢物的结构和生物合成起源，我们开发了一种基于质谱的策略，将无监督子结构预测与稳定同位素标记相结合，称为MAS-SILAC（通过细胞培养中的氨基酸进行子结构发现和稳定同位素标记辅助的代谢物注释）。这种方法导致发现了尿黑酸是几种天然产物生物合成和甲氧苄啶生物转化的前体，这代表了一种以前未知的抗生素耐受机制。这项工作展示了计算方法在分析非靶向代谢组学数据以将致病微生物的化学型与特定表型联系起来方面的应用。本研究中的观察结果为黑色素化表型的临床意义提供了见解。
