PDBsum entry 1k1k

Oxygen storage/transport

PDB id: 1k1k

Contents

Protein chains

141 a.a. *

146 a.a. *

Ligands

HEM-CMO ×2

Waters ×113

* Residue conservation analysis

PDB id:

1k1k

Name:

Oxygen storage/transport

Title:

Structure of mutant human carbonmonoxyhemoglobin c (beta e6k) at 2.0 angstrom resolution in phosphate buffer.

Structure:

Hemoglobin alpha chain. Chain: a. Hemoglobin beta chain. Chain: b. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Tissue: blood. Cell: erythrocyte. Cell: erythrocyte

Biol. unit:

Tetramer (from PDB file)

Resolution:

2.00Å R-factor: 0.183 R-free: 0.238

Authors:

J.C.Dewan,A.Taylor-Feeling,Y.A.Puius,L.Patskovska,Y.Patskovsky, R.L.Nagel,S.C.Almo,R.E.Hirsch

Key ref:

J.C.Dewan et al. (2002). Structure of mutant human carbonmonoxyhemoglobin C (betaE6K) at 2.0 A resolution. Acta Crystallogr D Biol Crystallogr, 58, 2038-2042. PubMed id: 12454462 DOI: 10.1107/S0907444902016426

Date:

25-Sep-01 Release date: 04-Dec-02

Protein chain

P69905  (HBA_HUMAN) -  Hemoglobin subunit alpha from Homo sapiens

Seq: 142 a.a.

Struc: 141 a.a.

Protein chain

P68871  (HBB_HUMAN) -  Hemoglobin subunit beta from Homo sapiens

Seq: 147 a.a.

Struc: 146 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.1107/S0907444902016426

Acta Crystallogr D Biol Crystallogr 58:2038-2042 (2002)

PubMed id: 12454462

Structure of mutant human carbonmonoxyhemoglobin C (betaE6K) at 2.0 A resolution.

J.C.Dewan, A.Feeling-Taylor, Y.A.Puius, L.Patskovska, Y.Patskovsky, R.L.Nagel, S.C.Almo, R.E.Hirsch.

ABSTRACT

Previous studies have demonstrated that in vitro crystallization of R-state liganded hemoglobin C (HbC), a naturally occurring mutant human hemoglobin (betaE6K), in high-phosphate buffer solutions provides a potential model system for the intracellular crystallization of HbC associated with chronic hemolytic anemia in CC disease. The first high-resolution crystal structure of liganded HbC is reported here. HbC was crystallized from high phosphate and the structure of the carbonmonoxy-liganded R-state form was refined at 2.0 A resolution. Crystals exhibit diffraction consistent with the tetragonal space group P4(1)2(1)2, with unit-cell parameters a = 54.16, c = 195.30 A. The structure was solved by difference Fourier techniques and refinement by simulated annealing and restrained least-squares yielded a final R of 0.183 and an R(free) of 0.238 for all 19,382 unique reflections. The side chain of betaK6 exhibits very weak electron density consistent with significant mobility within the crystalline lattice. The highly dynamic nature of the side chain could potentially support a number of specific polar interactions that might reduce the barrier to crystallization and thus result in enhanced crystallization kinetics for HbC relative to HbA. Specifically, the NZ atom of the BK6 side chain could participate in an amino-aromatic hydrogen bond with the pi-electron cloud of betaH116 in a symmetry-related tetramer. BetaK6 NZ might also interact with the main-chain carbonyl O atom of betaH117 and the carboxylate group of betaE22 from a symmetry-related tetramer.

Selected figure(s)

Figure 2.
Figure 2 Electron-density map of the -chain heme pocket of the 2 resolution of COHbC showing the high quality of the electron-density map, as exemplified by the proximal and distal histidines, and the heme group and CO molecule. Stereoview of 2F[o] - F[c] electron-density contour map built around the heme, His58 and His87 of the -subunit of COHbC.

The above figure is reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2002, 58, 2038-2042) copyright 2002.

Figure was selected by an automated process.