期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：35
页码：15335-15339
DOI：10.1073/pnas.1009648107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Manganese is an essential transition metal that, among other functions, can act independently of proteins to either defend against or promote oxidative stress and disease. The majority of cellular manganese exists as low molecular-weight Mn2+ complexes, and the balance between opposing "essential" and "toxic" roles is thought to be governed by the nature of the ligands coordinating Mn2+. Until now, it has been impossible to determine manganese speciation within intact, viable cells, but we here report that this speciation can be probed through measurements of 1H and 31P electron-nuclear double resonance (ENDOR) signal intensities for intracellular Mn2+. Application of this approach to yeast (Saccharomyces cerevisiae) cells, and two pairs of yeast mutants genetically engineered to enhance or suppress the accumulation of manganese or phosphates, supports an in vivo role for the orthophosphate complex of Mn2+ in resistance to oxidative stress, thereby corroborating in vitro studies that demonstrated superoxide dismutase activity for this species.
