1WLS

Crystal structure of L-asparaginase I homologue protein from Pyrococcus horikoshii

Summary for 1WLS

• Entry DOI: 10.2210/pdb1wls/pdb
• Descriptor: L-asparaginase (2 entities in total)
• Functional Keywords: structural genomics, hydrolase
• Biological source: Pyrococcus horikoshii
• Total number of polymer chains: 2
• Total formula weight: 73684.01

Authors

Yao, M.,Morita, H.,Yasutake, Y.,Tanaka, I. (deposition date: 2004-06-29, release date: 2005-03-15, Last modification date: 2024-10-23)

Primary citation

Yao, M.,Yasutake, Y.,Morita, H.,Tanaka, I.
Structure of the type I L-asparaginase from the hyperthermophilic archaeon Pyrococcus horikoshii at 2.16 angstroms resolution.
Acta Crystallogr.,Sect.D, 61:294-301, 2005

PubMed Abstract: The crystal structure of the L-asparaginase from the hyperthermophilic archaeon Pyrococcus horikoshii (PhA) was determined by the multiwavelength anomalous diffraction (MAD) method and was refined to a resolution of 2.16 angstroms with a crystallographic R factor and free R factor of 21.1 and 25.3%, respectively. This is the first report of the three-dimensional structure of a type I L-asparaginase. These enyzmes are known as cytosolic L-asparaginases with lower affinities for substrate than the type II L-asparaginases. Although the overall fold of PhA was closely related to the structure of the well characterized type II L-asparaginase, structural differences were also detected. PhA forms a homodimer that corresponds to half the homotetramer of type II L-asparaginases. Structure comparison at the active site reveals that most catalytic residues are conserved except for two residues that recognize the amino group of the substrate. Additionally, a remarkable structural difference is found in the so-called 'active-site flexible loop'. In PhA this loop is stabilized by beta-hairpin formation and by elaborate interactions with the type-I-specific alpha-helical region derived from the other subunit forming the PhA dimer. The flexible loop of the type II enzyme is considered to serve as a mobile gate to the active site. Therefore, the loop stabilization observed in the PhA structure may cause limitation of the access of the substrate to the active site.

PubMed: 15735339
DOI: 10.1107/S0907444904032950

Experimental method

X-RAY DIFFRACTION (2.16 Å)