4C0N
Crystal structure of non symbiotic plant hemoglobin AHb3 (GLB3) from Arabidopsis thaliana
Summary for 4C0N
| Entry DOI | 10.2210/pdb4c0n/pdb |
| Descriptor | 2-ON-2 HEMOGLOBIN, CHLORIDE ION, HYDROXIDE ION, ... (5 entities in total) |
| Functional Keywords | oxygen transport, 2-over-2 fold |
| Biological source | ARABIDOPSIS THALIANA (THALE CRESS) |
| Total number of polymer chains | 1 |
| Total formula weight | 20892.54 |
| Authors | Hough, M.A.,Reeder, B.J. (deposition date: 2013-08-06, release date: 2014-05-14, Last modification date: 2024-05-08) |
| Primary citation | Reeder, B.J.,Hough, M.A. The Structure of a Class 3 Nonsymbiotic Plant Haemoglobin from Arabidopsis Thaliana Reveals a Novel N-Terminal Helical Extension Acta Crystallogr.,Sect.D, 70:1411-, 2014 Cited by PubMed Abstract: Plant nonsymbiotic haemoglobins fall into three classes, each with distinct properties but all with largely unresolved physiological functions. Here, the first crystal structure of a class 3 nonsymbiotic plant haemoglobin, that from Arabidopsis thaliana, is reported to 1.77 Å resolution. The protein forms a homodimer, with each monomer containing a two-over-two α-helical domain similar to that observed in bacterial truncated haemoglobins. A novel N-terminal extension comprising two α-helices plays a major role in the dimer interface, which occupies the periphery of the dimer-dimer face, surrounding an open central cavity. The haem pocket contains a proximal histidine ligand and an open sixth iron-coordination site with potential for a ligand, in this structure hydroxide, to form hydrogen bonds to a tyrosine or a tryptophan residue. The haem pocket appears to be unusually open to the external environment, with another cavity spanning the entrance of the two haem pockets. The final 23 residues of the C-terminal domain are disordered in the structure; however, these domains in the functional dimer are adjacent and include the only two cysteine residues in the protein sequence. It is likely that these residues form disulfide bonds in vitro and it is conceivable that this C-terminal region may act in a putative complex with a partner molecule in vivo. PubMed: 24816109DOI: 10.1107/S1399004714004878 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.77 Å) |
Structure validation
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