2LHM

CRYSTAL STRUCTURES OF THE APO-AND HOLOMUTANT HUMAN LYSOZYMES WITH AN INTRODUCED CA2+ BINDING SITE

Summary for 2LHM

• Entry DOI: 10.2210/pdb2lhm/pdb
• Descriptor: HUMAN LYSOZYME (2 entities in total)
• Functional Keywords: hydrolase (o-glycosyl)
• Biological source: Homo sapiens (human)
• Cellular location: Secreted: P61626
• Total number of polymer chains: 1
• Total formula weight: 14751.66

Authors

Inaka, K.,Matsushima, M. (deposition date: 1991-10-02, release date: 1992-04-15, Last modification date: 2024-11-13)

Primary citation

Inaka, K.,Kuroki, R.,Kikuchi, M.,Matsushima, M.
Crystal structures of the apo- and holomutant human lysozymes with an introduced Ca2+ binding site.
J.Biol.Chem., 266:20666-20671, 1991

PubMed Abstract: The three-dimensional structures of apo- and holomutant human lysozymes (D86/92 lysozyme), in which a calcium binding site was designed and created for enhancing molecular stability by replacing both Gln86 and Ala92 with aspartic acids, were refined at 1.8-A resolution by x-ray crystallography. The overall structures and crystallographic thermal factors of all three proteins, the apo-, holo-D86/92, and the wild-type human lysozymes, were essentially identical; these results showed that the introduction of the calcium binding site did not affect either the overall structure or molecular rigidity of the proteins. However, structure analyses of the apo-D86/92 lysozyme revealed that the mutations affected the side chain conformation of residue 86 and hydrogen networks between the protein and the internal solvent molecules. In the structure of the holo-D86/92 lysozyme, seven oxygen ligands formed a slightly distorted pentagonal bipyramid around the calcium ion, indicating that the coordination around the calcium ion was quite similar to that in baboon alpha-lactalbumin. The pentagonal bipyramid coordination could be one of the most widely found and appropriate calcium binding schemes in proteins.

PubMed: 1939116

Experimental method

X-RAY DIFFRACTION (1.8 Å)