1EBG

CHELATION OF SER 39 TO MG2+ LATCHES A GATE AT THE ACTIVE SITE OF ENOLASE: STRUCTURE OF THE BIS(MG2+) COMPLEX OF YEAST ENOLASE AND THE INTERMEDIATE ANALOG PHOSPHONOACETOHYDROXAMATE AT 2.1 ANGSTROMS RESOLUTION

Summary for 1EBG

• Entry DOI: 10.2210/pdb1ebg/pdb
• Descriptor: ENOLASE, MAGNESIUM 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: 2
• Total formula weight: 93872.91

Authors

Wedekind, J.E.,Reed, G.H.,Rayment, I. (deposition date: 1994-04-27, release date: 1995-04-27, Last modification date: 2024-02-07)

Primary citation

Wedekind, J.E.,Poyner, R.R.,Reed, G.H.,Rayment, I.
Chelation of serine 39 to Mg2+ latches a gate at the active site of enolase: structure of the bis(Mg2+) complex of yeast enolase and the intermediate analog phosphonoacetohydroxamate at 2.1-A resolution.
Biochemistry, 33:9333-9342, 1994

PubMed Abstract: The structure of a new crystal form of enolase from bakers' yeast has been solved to 2.1-A resolution. Crystals were grown from poly(ethylene glycol) and KCl at pH 8.2 in the presence of Mg2+ and a reaction intermediate analog, phosphonoacetohydroxamate (PhAH). Crystals belong to space group C2; have unit cell dimensions a = 123.5 A, b = 73.9 A, and c = 94.8 A with beta = 93.3 degrees; and contain one dimer per asymmetric unit. The structure was solved by molecular replacement from the X-ray coordinates of apoenolase [Stec, B., & Lebioda, L. (1990) J. Mol. Biol. 211, 235-248]. Both essential divalent metal ions are observed to be complexed with the inhibitor. The two Mg2+ ions are 4.05 A apart and are bridged by a mu-oxyl ligand from the carbonyl moiety of PhAH. The "high-affinity" Mg2+ coordinates to the carboxylate side chains of Asp 246, Glu 295, and Asp 320, one water molecule, and the hydroxamate and carbonyl oxygens of PhAH. The second Mg2+ coordinates to a phosphonyl oxygen, two water molecules, and the mu-bridge carbonyl oxygen of PhAH. Coordination schemes with respect to PhAH and water ligands are fully consistent with those of the Mn2+ complexes determined spectroscopically [Poyner, R.R., & Reed, G. H. (1992) Biochemistry 31, 7166-7173]. Remaining ligands for the second Mg2+ are the carbonyl oxygen and gamma-oxygen of Ser 39. Chelation of this Ser residue to Mg2+ effectively "latches" a flexible loop extending from Gly 37 through His 43 and closes off the entrance to the active site. The position of the second Mg2+ in the active site provides new insight into the stereochemistry of substrate binding.

PubMed: 8049235
DOI: 10.1021/bi00197a038

Experimental method

X-RAY DIFFRACTION (2.1 Å)