a possible co2 conducting and concentrating mechanism in plant stomata slac1 channel一个可能的二氧化碳进行集中机制在植物气孔slac1通道.pdfVIP

A Possible CO2 Conducting and Concentrating Mechanism in Plant Stomata SLAC1 Channel 1,2,4 2 1,3 1,2,3 Qi-Shi Du *, Xina-Wei Fan , Cheng-Hua Wang , Ri-Bo Huang 1 National Engineering Research Center for Non-Food Biorefinery, Guangxi Academy of Sciences, Nanning, China, 2 College of Life Science and Technology, Guangxi University, Nanning, China, 3 Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing, China, 4 Gordon Life Science Institute, San Diego, California, United States of America Abstract Background: The plant SLAC1 is a slow anion channel in the membrane of stomatal guard cells, which controls the turgor pressure in the aperture-defining guard cells, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals such as drought, high levels of carbon dioxide, and bacterial invasion. Recent study demonstrated that bicarbonate is a small-molecule activator of SLAC1. Higher CO2 and HCO3– concentration activates S- type anion channel currents in wild-type Arabidopsis guard cells. Based on the SLAC1 structure a theoretical model is derived to illustrate the activation of bicarbonate to SLAC1 channel. Meanwhile a possible CO2 conducting and concentrating mechanism of the SLAC1 is proposed. Methodology: The homology structure of Arabidopsis thaliana SLAC1 (AtSLAC1) provides the structural basis for study of the conducting and concentrating mechanism of carbon dioxide in SLAC1 channels. The pKa values of ionizable amino acid side chains in AtSLAC1 are calculated using software PROPKA3.0, and the concentration of CO2 and anion HCO3– are