4XDI

Structure of Chlamydomonas reinhardtii THB1

Summary for 4XDI

• Entry DOI: 10.2210/pdb4xdi/pdb
• Descriptor: Chlamydomonas reinhardtii THB1, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: group 1 truncated hemoglobin, trhbn, trhb1, heme binding protein
• Biological source: Chlamydomonas reinhardtii
• Total number of polymer chains: 2
• Total formula weight: 30399.85

Authors

Rice, S.L.,Boucher, L.E.,Schlessman, J.L.,Bosch, J.,Lecomte, J.T.J. (deposition date: 2014-12-19, release date: 2015-01-21, Last modification date: 2024-02-28)

Primary citation

Rice, S.L.,Boucher, L.E.,Schlessman, J.L.,Preimesberger, M.R.,Bosch, J.,Lecomte, J.T.
Structure of Chlamydomonas reinhardtii THB1, a group 1 truncated hemoglobin with a rare histidine-lysine heme ligation.
Acta Crystallogr.,Sect.F, 71:718-725, 2015

PubMed Abstract: THB1 is one of several group 1 truncated hemoglobins (TrHb1s) encoded in the genome of the unicellular green alga Chlamydomonas reinhardtii. THB1 expression is under the control of NIT2, the master regulator of nitrate assimilation, which also controls the expression of the only nitrate reductase in the cell, NIT1. In vitro and physiological evidence suggests that THB1 converts the nitric oxide generated by NIT1 into nitrate. To aid in the elucidation of the function and mechanism of THB1, the structure of the protein was solved in the ferric state. THB1 resembles other TrHb1s, but also exhibits distinct features associated with the coordination of the heme iron by a histidine (proximal) and a lysine (distal). The new structure illustrates the versatility of the TrHb1 fold, suggests factors that stabilize the axial ligation of a lysine, and highlights the difficulty of predicting the identity of the distal ligand, if any, in this group of proteins.

PubMed: 26057801
DOI: 10.1107/S2053230X15006949

Experimental method

X-RAY DIFFRACTION (1.893 Å)