1AJ9

R-STATE HUMAN CARBONMONOXYHEMOGLOBIN ALPHA-A53S

Summary for 1AJ9

• Entry DOI: 10.2210/pdb1aj9/pdb
• Descriptor: HEMOGLOBIN (ALPHA CHAIN), HEMOGLOBIN (BETA CHAIN), PHOSPHATE ION, ... (6 entities in total)
• Functional Keywords: oxygen transport, hemoglobin, mutant, alpha-a53s, carboxyhemoglobin, carbonmonoxide, carbonmonoxyhemoglobin, carbonmonoxy
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 2
• Total formula weight: 32440.52

Authors

Vasquez, G.B.,Ji, X.,Fronticelli, C.,Gilliland, G.L. (deposition date: 1997-05-16, release date: 1998-05-20, Last modification date: 2023-08-30)

Primary citation

Vasquez, G.B.,Ji, X.,Fronticelli, C.,Gilliland, G.L.
Human carboxyhemoglobin at 2.2 A resolution: structure and solvent comparisons of R-state, R2-state and T-state hemoglobins.
Acta Crystallogr.,Sect.D, 54:355-366, 1998

PubMed Abstract: The three-dimensional structure and associated solvent of human carboxyhemoglobin at 2.2 A resolution are compared with other R-state and T-state human hemoglobin structures. The crystal form is isomorphous with that of the 2.7 A structure of carboxyhemoglobin reported earlier [Baldwin (1980). J. Mol. Biol. 136, 103-128], whose coordinates were used as a starting model, and with the 2.2 A structure described in an earlier report [Derewenda et al. (1990). J. Mol. Biol. 211, 515-519]. During the course of the refinement, a natural mutation of the alpha-subunit, A53S, was discovered that forms a new crystal contact through a bridging water molecule. The protein structure shows a significant difference between the alpha and beta heme geometries, with Fe-C-O angles of 125 and 162 degrees, respectively. The carboxyhemoglobin is compared with other fully ligated R-state human hemoglobins [Baldwin (1980). J. Mol. Biol. 136, 103-128; Shaanan (1983). J. Mol. Biol. 195, 419-422] with the R2-state hemoglobin [Silva et al. (1992). J. Biol. Chem. 267, 17248-17256] and with T-state deoxyhemoglobin [Fronticelli et al. (1994). J. Biol. Chem. 269, 23965-23969]. The structure is similar to the earlier reported R-state structures, but there are differences in many side-chain conformations, the associated water structure and the presence and the position of a phosphate ion. The quaternary changes between the R-state carboxyhemoglobin and the R2-state and T-state structures are in general consistent with those reported in the earlier structures. The location of 238 water molecules and a phosphate ion in the carboxyhemoglobin structure allows the first comparison of the solvent structures of the R-state and T-state structures. Distinctive hydration patterns for each of the quaternary structures are observed, but a number of conserved water molecule binding sites are found that are independent of the conformational state of the protein.

PubMed: 9761903
DOI: 10.1107/S0907444997012250

Experimental method

X-RAY DIFFRACTION (2.2 Å)