Molecular Basis of Signal Transduction of High Intensity Light via Nucleoside Diphosphate Kinase (NDPK) in Neurospora Crassa and Pisum Sativum cv Alaska (pp. 149-162)
Authors: (Kohji Hasunuma, Yusuke Yoshida, Md. Emdadul Haque, Kihara Institute for Biological Research, Yokohama City University, Totsuka-ku, Yokohama, Japan, and others)
Abstract: The molecular basis of signal transduction immediately after reception of strong light including sunlight by Neurospora crassa and Pisum sativum cv Alaska was described. The functional role of photoreceptor is likely to be photosensitizing capacity transferring the energy of light to ambient triplet oxygen emitting singlet oxygen. The singlet oxygen evolved is captured by catalase (CAT) at the prosthetic group of heme. To such CAT molecules binding singlet oxygen nucleoside diphosphate kinase (NDPK) will interact, which had the capacity to bind NADH. We disclosed the function of this process, which invoked the transferring of electron from bound NADH on NDPK to singlet oxygen on CAT releasing super oxide. The detoxification processes from hydrogen peroxide to water and oxygen gas will also be controlled by the protein interaction between NDPK and CAT molecules, and NDPK binding NADH will interact with CAT binding hydrogen peroxide hastening the reducing reaction in vivo. The protein interaction between NDPK and CAT may change upon reception of singlet oxygen and permit the phosphorylation of NDPK. The phosphate group on NDPK is transferred to several
molecules indicating a hitherto unknown phospho-transferring signal transduction cascade. We obtained a mutant R3-1 resistant to reactive oxygen species (ROS) induced by paraquat, which showed high yielding of silic in Pisum sativum cv Alaska. The cloned mutant molecule of NDPK2 with transit peptide localizing on the surface of chloroplast and cytosol showed high capacity to be autophosphorylated compared with the wild type molecule with transit peptide. The overall process of detoxification of singlet oxygen showing very short lifetime to super oxide and to hydrogen peroxide was figured out. In Neurospora crassa mitochondria can function as an organella producing ROS, which may be controlled by ROS during the mating process. ROS resistant mutants with incomplete carotenoid synthesis showed characteristics of father inheritance. The whole processes may be generated during the process of early development of plant from algae in the sea and lake to land plants in the history of the earth.