Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), Argentina.
FEBS Lett. 2024 Nov;598(21):2702-2716. doi: 10.1002/1873-3468.15000. Epub 2024 Aug 16.
Pyomelanin, a polymeric pigment in Pseudomonas, arises mainly from alterations in tyrosine degradation. The chemical structure of pyomelanin remains elusive due to its heterogeneous nature. Here, we report strain-specific differences in pyomelanin structural features across Pseudomonas using PAO1 and PA14 reference strains carrying mutations in hmgA (a gene involved in pyomelanin synthesis), a melanogenic P. aeruginosa clinical isolate (PAM), and a melanogenic P. extremaustralis (PexM). UV spectra showed dual peaks for PAO1 and PA14 mutants and single peaks for PAM and PexM. FTIR phenol : alcohol ratio changes and complex NMR spectra indicated non-linear polymers. UVC radiation survival increased with pyomelanin addition, correlating with pigment absorption attenuation. P. extremaustralis UVC survival varied with melanin source, with PAO1 pyomelanin being the most protective. These findings delineate structure-based pyomelanin subgroups, having distinct physiological effects.
铜绿假单胞菌中的聚合色素吡咯并喹啉醌（Pyomelanin）主要来源于酪氨酸降解的改变。由于其异质性，吡咯并喹啉醌的化学结构仍然难以捉摸。在这里，我们使用 PAO1 和 PA14 参考菌株报告了铜绿假单胞菌中吡咯并喹啉醌结构特征的菌株特异性差异，这些参考菌株携带 hmgA（参与吡咯并喹啉醌合成的基因）突变、一个产黑色素的铜绿假单胞菌临床分离株（PAM）和一个产黑色素的极端假单胞菌（PexM）。紫外光谱显示 PAO1 和 PA14 突变体有双峰，而 PAM 和 PexM 只有单峰。傅里叶变换红外（FTIR）中苯酚：醇比值的变化和复杂的核磁共振（NMR）谱表明存在非线性聚合物。随着吡咯并喹啉醌的添加，UVC 辐射存活率增加，与色素吸收衰减相关。极端假单胞菌的 UVC 存活率随黑色素来源而变化，其中 PAO1 吡咯并喹啉醌的保护作用最强。这些发现描绘了基于结构的吡咯并喹啉醌亚群，具有不同的生理效应。
