1XZ4

Intersubunit Interactions Associated with Tyr42alpha Stabilize the Quaternary-T Tetramer but are not Major Quaternary Constraints in Deoxyhemoglobin: alphaY42A deoxyhemoglobin no-salt

Summary for 1XZ4

• Entry DOI: 10.2210/pdb1xz4/pdb
• Related: 1RQ3 1XYE 1XZ2
• Descriptor: Hemoglobin alpha chain, Hemoglobin beta chain, PROTOPORPHYRIN IX CONTAINING FE, ... (4 entities in total)
• Functional Keywords: hemoglobin mutant, globin, transport protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 4
• Total formula weight: 64426.99

Authors

Kavanaugh, J.S.,Rogers, P.H.,Arnone, A.,Hui, H.L.,Wierzba, A.,DeYoung, A.,Kwiatkowski, L.D.,Noble, R.W.,Juszczak, L.J.,Peterson, E.S.,Friedman, J.M. (deposition date: 2004-11-11, release date: 2004-11-30, Last modification date: 2023-08-23)

Primary citation

Kavanaugh, J.S.,Rogers, P.H.,Arnone, A.,Hui, H.L.,Wierzba, A.,Deyoung, A.,Kwiatkowski, L.D.,Noble, R.W.,Juszczak, L.J.,Peterson, E.S.,Friedman, J.M.
Intersubunit interactions associated with tyr42alpha stabilize the quaternary-T tetramer but are not major quaternary constraints in deoxyhemoglobin
Biochemistry, 44:3806-3820, 2005

PubMed Abstract: Previous mutational studies on Tyr42alpha variants as well as the current studies on the mutant hemoglobin alphaY42A show that the intersubunit interactions associated with Tyr42alpha significantly stabilize the alpha1beta2 interface of the quaternary-T deoxyhemoglobin tetramer. However, crystallographic studies, UV and visible resonance Raman spectroscopy, CO combination kinetic measurements, and oxygen binding measurements on alphaY42A show that the intersubunit interactions formed by Tyr42alpha have only a modest influence on the structural properties and ligand affinity of the deoxyhemoglobin tetramer. Therefore, the alpha1beta2 interface interactions associated with Tyr42alpha do not contribute significantly to the quaternary constraints that are responsible for the low oxygen affinity of deoxyhemoglobin. The slight increase in the ligand affinity of deoxy alphaY42A correlates with small, mutation-induced structural changes that perturb the environment of Trp37beta, a critical region of the quaternary-T alpha1beta2 interface that has been shown to be the major source of quaternary constraint in deoxyhemoglobin.

PubMed: 15751957
DOI: 10.1021/bi0484670

Experimental method

X-RAY DIFFRACTION (2 Å)