PDBsum entry 1a3n

Oxygen transport

PDB id: 1a3n

Contents

Protein chains

141 a.a. *

145 a.a. *

Ligands

HEM ×4

Waters ×455

* Residue conservation analysis

References listed in PDB file

Key reference

Title

The structures of deoxy human haemoglobin and the mutant hb tyralpha42his at 120 k.

Authors

J.R.Tame, B.Vallone.

Ref.

Acta Crystallogr D Biol Crystallogr, 2000, 56, 805-811. [DOI no: 10.1107/S0907444900006387]

PubMed id

10930827

Abstract

The structures of deoxy human haemoglobin and an artificial mutant (Tyralpha42-->His) have been solved at 120 K. While overall agreement between these structures and others in the PDB is very good, certain side chains are found to be shifted, absent from the electron-density map or in different rotamers. Non-crystallographic symmetry (NCS) is very well obeyed in the native protein, but not around the site of the changed residue in the mutant. NCS is also not obeyed by the water molecule invariably found in the alpha-chain haem pocket in room-temperature crystal structures of haemoglobin. At 120 K, this water molecule disappears from one alpha chain in the asymmetric unit but not the other.

Figure 1.
Figure 1 The [1] haem. The 2F[o] - F[c] electron-density map is contoured at 1 .

Figure 3.
Figure 3 His [1]42. The 2F[o] - F[c] electron-density map shows the residues neighbouring [1]42 are undisturbed by the mutation from tyrosine.

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2000, 56, 805-811) copyright 2000.