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Báo cáo sinh học: "Adaptations of proteins to cellular and subcellular pH"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Adaptations of proteins to cellular and subcellular pH. | Journal of Biology Minireview Adaptations of proteins to cellular and subcellular pH Bertrand Garcia-Moreno Address Department of Biophysics Johns Hopkins University Baltimore MD 21218 USA. Email bertrand@jhu.edu Abstract Bioinformatics-based searches for correlations between sub-cellular localization and pI or charge distribution of proteins have failed to detect meaningful correlations. Recent work published in BMC Biology finds that a physicochemical metric of charge distribution correlates better with subcellular pH than does pI. See research article http www.biomedcentral.com 1741-7007 7 69 The need for tight regulation of intracellular pH is one of the most important and constant organizing principles of living systems. It is essential because the fundamental energy transduction machinery of cells runs mainly on H gradients and proton-coupled electron transfer reactions. It is also necessary because pH determines the charge state of weak acids and bases for example side chains of Asp Glu His Lys and Arg and so on and the charge state in turn affects many physical and physiological properties of biological molecules especially proteins and RNAs Figure 1 . Regulation of intracellular pH is so central to the living state that even the most primitive cells capable of energy transduction must have been able to control intracellular pH by expelling H produced from the hydrolysis of organic compounds. How tightly is pH regulated in cells and organisms Consider that the normal pH of human arterial blood is 7.40. Depression below pH 7.35 leads to acidosis a condition that requires medical attention and elevation to pH 7.50 results in alkalosis responsible for the unpleasant symptoms of altitude sickness. Similarly small changes of 0.1 pH units in intracellular pH or within subcellular compartments can have physiological consequences. What is remarkable is that despite the need for very tight regulation the pH in various cellular compartments varies significantly. In .