3W4U

Human zeta-2 beta-2-s hemoglobin

Summary for 3W4U

• Entry DOI: 10.2210/pdb3w4u/pdb
• Related: 1hbs 1jeb
• Descriptor: Hemoglobin subunit zeta, Hemoglobin subunit beta, PROTOPORPHYRIN IX CONTAINING FE, ... (5 entities in total)
• Functional Keywords: globin fold, oxygen transport, oxygen binding, carbon mono-oxide bound, blood
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 6
• Total formula weight: 98424.65

Authors

Safo, M.K.,Ko, T.-P.,Russell, J.E. (deposition date: 2013-01-16, release date: 2013-02-06, Last modification date: 2023-11-08)

Primary citation

Safo, M.K.,Ko, T.-P.,Abdulmalik, O.,He, Z.,Wang, A.H.,Schreiter, E.R.,Russell, J.E.
Structure of fully liganded Hb zeta 2 beta 2(s) trapped in a tense conformation
Acta Crystallogr.,Sect.D, 69:2061-2071, 2013

PubMed Abstract: A variant Hb ζ2β2(s) that is formed from sickle hemoglobin (Hb S; α2β2(s)) by exchanging adult α-globin with embryonic ζ-globin subunits shows promise as a therapeutic agent for sickle-cell disease (SCD). Hb ζ2β2(s) inhibits the polymerization of deoxygenated Hb S in vitro and reverses characteristic features of SCD in vivo in mouse models of the disorder. When compared with either Hb S or with normal human adult Hb A (α2β2), Hb ζ2β2(s) exhibits atypical properties that include a high oxygen affinity, reduced cooperativity, a weak Bohr effect and blunted 2,3-diphosphoglycerate allostery. Here, the 1.95 Å resolution crystal structure of human Hb ζ2β2(s) that was expressed in complex transgenic knockout mice and purified from their erythrocytes is presented. When fully liganded with carbon monoxide, Hb ζ2β2(s) displays a central water cavity, a ζ1-β(s)2 (or ζ2-β(s)1) interface, intersubunit salt-bridge/hydrogen-bond interactions, C-terminal βHis146 salt-bridge interactions, and a β-cleft, that are highly unusual for a relaxed hemoglobin structure and are more typical of a tense conformation. These quaternary tense-like features contrast with the tertiary relaxed-like conformations of the ζ1β(s)1 dimer and the CD and FG corners, as well as the overall structures of the heme cavities. This crystallographic study provides insights into the altered oxygen-transport properties of Hb ζ2β2(s) and, moreover, decouples tertiary- and quaternary-structural events that are critical to Hb ligand binding and allosteric function.

PubMed: 24100324
DOI: 10.1107/S0907444913019197

Experimental method

X-RAY DIFFRACTION (1.95 Å)