2XYK

Group II 2-on-2 Hemoglobin from the Plant Pathogen Agrobacterium tumefaciens

Summary for 2XYK

• Entry DOI: 10.2210/pdb2xyk/pdb
• Descriptor: 2-ON-2 HEMOGLOBIN, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: oxygen storage-transport complex, 2/2 hemoglobin, oxygen storage/transport
• Biological source: AGROBACTERIUM TUMEFACIENS
• Total number of polymer chains: 2
• Total formula weight: 31745.65

Authors

Pesce, A.,Nardini, M.,LaBarre, M.,Richard, C.,Wittenberg, J.B.,Wittenberg, B.A.,Guertin, M.,Bolognesi, M. (deposition date: 2010-11-18, release date: 2010-12-01, Last modification date: 2023-12-20)

Primary citation

Pesce, A.,Nardini, M.,Labarre, M.,Richard, C.,Wittenberg, J.B.,Wittenberg, B.A.,Guertin, M.,Bolognesi, M.
Structural Characterization of a Group II 2/2 Hemoglobin from the Plant Pathogen Agrobacterium Tumefaciens.
Biochim.Biophys.Acta, 1814:810-, 2011

PubMed Abstract: Within the 2/2 hemoglobin sub-family, no group II 2/2Hbs from proteobacteria have been so far studied. Here we present the first structural characterization of a group II 2/2Hb from the soil and phytopathogenic bacterium Agrobacterium tumefaciens (At-2/2HbO). The crystal structure of ferric At-2/2HbO (reported at 2.1Å resolution) shows the location of specific/unique heme distal site residues (e.g., His(42)CD1, a residue distinctive of proteobacteria group II 2/2Hbs) that surround a heme-liganded water molecule. A highly intertwined hydrogen-bonded network, involving residues Tyr(26)B10, His(42)CD1, Ser(49)E7, Trp(93)G8, and three distal site water molecules, stabilizes the heme-bound ligand. Such a structural organization suggests a path for diatomic ligand diffusion to/from the heme. Neither a similar distal site structuring effect nor the presence of distal site water molecules has been so far observed in group I and group III 2/2Hbs, thus adding new distinctive information to the complex picture of currently available 2/2Hb structural and functional data. This article is part of a Special Issue entitled: Protein Structure and Function in the Crystalline State.

PubMed: 21070893
DOI: 10.1016/J.BBAPAP.2010.11.001

Experimental method

X-RAY DIFFRACTION (2.1 Å)