1NCL

THERMAL STABILITY OF HEXAMERIC AND TETRAMERIC NUCLEOSIDE, DIPHOSPHATE KINASES

Summary for 1NCL

• Entry DOI: 10.2210/pdb1ncl/pdb
• Descriptor: NUCLEOSIDE DIPHOSPHATE KINASE (2 entities in total)
• Functional Keywords: enzyme, transferase, kinase, atp-binding
• Biological source: Dictyostelium discoideum
• Cellular location: Cytoplasm: P22887
• Total number of polymer chains: 1
• Total formula weight: 16213.61

Authors

Janin, J.,Morera, S.,Lascu, I. (deposition date: 1996-03-22, release date: 1996-11-08, Last modification date: 2024-02-14)

Primary citation

Giartosio, A.,Erent, M.,Cervoni, L.,Morera, S.,Janin, J.,Konrad, M.,Lascu, I.
Thermal stability of hexameric and tetrameric nucleoside diphosphate kinases. Effect of subunit interaction.
J.Biol.Chem., 271:17845-17851, 1996

PubMed Abstract: The eukaryotic nucleoside diphosphate (NDP) kinases are hexamers, while the bacterial NDP kinases are tetramers made of small, single domain subunits. These enzymes represent an ideal model for studying the effect of subunit interaction on protein stability. The thermostability of NDP kinases of each class was studied by differential scanning calorimetry and biochemical methods. The hexameric NDP kinase from Dictyostelium discoideum displays one single, irreversible differential scanning calorimetry peak (Tm 62 degrees C) over a broad protein concentration, indicating a single step denaturation. The thermal stability of the protein was increased by ADP. The P105G substitution, which affects a loop implicated in subunit contacts, yields a protein that reversibly dissociates to folded monomers at 38 degrees C before the irreversible denaturation occurs (Tm 47 degrees C). ADP delays the dissociation, but does not change the Tm. These data indicate a "coupling" of the quaternary structure with the tertiary structure in the wild-type, but not in the mutated protein. We describe the x-ray structure of the P105G mutant at 2.2-A resolution. It is very similar to that of the wild-type protein. Therefore, a minimal change in the structure leads to a dramatic change of protein thermostability. The NDP kinase from Escherichia coli behaves like the P105G mutant of the Dictyostelium NDP kinase. The detailed study of their thermostability is important, since biological effects of thermolabile NDP kinases have been described in several organisms.

PubMed: 8663370
DOI: 10.1074/jbc.271.30.17845

Experimental method

X-RAY DIFFRACTION (2.2 Å)