Characterization of the Heme Pocket Structure and Ligand Binding Kinetics of Non-symbiotic Hemoglobins from the Model Legume Lotus japonicus.

ABSTRACT: Plant hemoglobins (Hbs) are found in nodules of legumes and actinorhizal plants but also in non-symbiotic organs of monocots and dicots. Non-symbiotic Hbs (nsHbs) have been classified into two phylogenetic groups. Class 1 nsHbs show an extremely high O₂ affinity and are induced by hypoxia and nitric oxide (NO), whereas class 2 nsHbs have moderate O₂ affinity and are induced by cold and cytokinins. The functions of nsHbs are still unclear, but some of them rely on the capacity of hemes to bind diatomic ligands and catalyze the NO dioxygenase (NOD) reaction (oxyferrous Hb + NO → ferric Hb + nitrate). Moreover, NO may nitrosylate Cys residues of proteins. It is therefore important to determine the ligand binding properties of the hemes and the role of Cys residues. Here,

SUBMITTER: Calvo-Begueria L 

PROVIDER: S-EPMC5378813 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature