1ELS

CATALYTIC METAL ION BINDING IN ENOLASE: THE CRYSTAL STRUCTURE OF ENOLASE-MN2+-PHOSPHONOACETOHYDROXAMATE COMPLEX AT 2.4 ANGSTROMS RESOLUTION

Summary for 1ELS

• Entry DOI: 10.2210/pdb1els/pdb
• Descriptor: ENOLASE, MANGANESE (II) ION, PHOSPHONOACETOHYDROXAMIC ACID, ... (4 entities in total)
• Functional Keywords: carbon-oxygen lyase
• Biological source: Saccharomyces cerevisiae (baker's yeast)
• Cellular location: Cytoplasm : P00924
• Total number of polymer chains: 1
• Total formula weight: 46955.61

Authors

Zhang, E.,Hatada, M.,Brewer, J.M.,Lebioda, L. (deposition date: 1994-04-05, release date: 1994-07-31, Last modification date: 2024-02-07)

Primary citation

Zhang, E.,Hatada, M.,Brewer, J.M.,Lebioda, L.
Catalytic metal ion binding in enolase: the crystal structure of an enolase-Mn2+-phosphonoacetohydroxamate complex at 2.4-A resolution.
Biochemistry, 33:6295-6300, 1994

PubMed Abstract: Enolase, a glycolytic enzyme that catalyzes the dehydration of 2-phospho-D-glycerate (PGA) to form phosphoenolpyruvate (PEP), requires two divalent metal ions per active site for activity. The first metal ion, traditionally referred to as "conformational", binds in a high-affinity site I. The second metal ion, "catalytic", binds in site II only in the presence of a substrate or substrate analogue and with much lower affinity for the physiological cofactor Mg2+. While the high-affinity site has been well characterized, the position of the lower affinity site has not been established so far. Here, we report the structure of the quaternary complex between enolase, the transition-state analogue phosphonoacetohydroxamate (PhAH), and two Mn2+ ions. The structure has been refined by using 16 561 reflections with F/sigma (F) > or = 3 to an R = 0.165 with average deviations of bond lengths and bond angles from ideal values of 0.013 A and 3.1 degrees, respectively. The "catalytic" metal ion is coordinated to two oxygen atoms of the phosphono moiety of PhAH and to the carbonyl oxygen of Gly37. Most likely, disordered water molecules complement its coordination sphere. The interaction with the site II metal ion must stabilize negative charge on the phosphate group and produce electron withdrawal from carbon 2 of the substrate, facilitating proton abstraction from carbon 2, the rate-limiting step in the catalytic process. The Gly37 residue is located in the flexible loop Ser36-His43, which assumes an "open" conformation in the absence of substrate and a "closed" conformation in the presence of a substrate.(ABSTRACT TRUNCATED AT 250 WORDS)

PubMed: 8193144
DOI: 10.1021/bi00186a032

Experimental method

X-RAY DIFFRACTION (2.4 Å)