Structure determination of glucose isomerase from Streptomyces murinus at 2.6 Å resolution

Abstract

Glucose isomerase from Streptomyces murinus has been crystallized in space group P4t2~2, cell dimensions a = b = 137.65 and c = 132.20 A. One dimer of the tetrametric molecule is found per asymmetric unit. An initial structure solution was obtained by the molecular replacement method. The crystallographic refinement was performed using molecular dynamics techniques with X-ray restraints. The final crystallographic R value is 21.4% at 2.6 A resolution including 3023 non-H atoms, two metal ions and two water molecules per monomer.

Crystal structures of thermostable xylose isomerases from Thermus caldophilus and Thermus thermophilus : possible structural determinants of thermostability 1 1Edited by D. Rees

“…In both TcaXI and TthXI models, the peptide bond between Glu185 and Pro186 takes a cis-conformation. The presence of a cis-peptide bond at this position and the energetically unfavorable backbone conformation at Glu185 have been observed previously for other XIs (Rasmussen et al, 1994;Whitlow et al, 1991;Dauter et al, 1990;Henrick et al, 1989). In both models of TcaXI and TthXI, Glu185 interacts with Lys182, a residue known to be involved in substrate binding.…”

“…Crystal structures of several class I XIs from mesophilic bacteria have been extensively characterized. They include XIs from A. missouriensis, Arthrobacter strain B3728, and Streptomyces species (Allen et al, 1995;Rasmussen et al, 1994;Lavie et al, 1994;Carrell et al, 1984Carrell et al, , 1987Carrell et al, , 1994Cha et al, 1994;Collyer et al, 1990Collyer et al, , 1992Blow et al, 1992;Jenkins et al, 1992;Whitlow et al, 1991;Dauter et al, 1990;Farber et al, 1989;Henrick et al, 1989;Rey et al, 1988). All known structures of class I XIs display a similar tetrameric arrangement.…”

Thermotoga neapolitana Homotetrameric Xylose Isomerase Is Expressed as a Catalytically Active and Thermostable Dimer in Escherichia coli

“…Xylose isomerase (XI) (EC 5.3.1.5) is a well-studied enzyme, in part because of its industrial significance as an immobilized biocatalyst in the production of high-fructose corn syrup (14,18). Amino acid sequences have been reported for at least 25 XIs (GenBank), and three-dimensional structures [characteristically (␣/␤) 8 barrels] have been resolved for several of them (6,9,11,12,15,20,21,29). Most known XIs are homotetramers with molecular masses of approximately 45 to 50 kDa per subunit, although some XIs have been found to be dimeric (3,15,17,25).…”