1I0A

CRYSTAL STRUCTURE OF WILD TYPE TURKEY DELTA 1 CRYSTALLIN (EYE LENS PROTEIN)

Summary for 1I0A

• Entry DOI: 10.2210/pdb1i0a/pdb
• Related: 1DCN 1HY0 1HY1
• Descriptor: DELTA CRYSTALLIN I (2 entities in total)
• Functional Keywords: eye lens protein, delta 1 crystallin, argininosuccinate lyase, lyase
• Biological source: Meleagris gallopavo (turkey)
• Total number of polymer chains: 4
• Total formula weight: 203570.83

Authors

Sampaleanu, L.M.,Vallee, F.,Slingsby, C.,Howell, P.L. (deposition date: 2001-01-29, release date: 2001-04-21, Last modification date: 2024-02-07)

Primary citation

Sampaleanu, L.M.,Vallee, F.,Slingsby, C.,Howell, P.L.
Structural studies of duck delta 1 and delta 2 crystallin suggest conformational changes occur during catalysis.
Biochemistry, 40:2732-2742, 2001

PubMed Abstract: Duck delta1 and delta2 crystallin are 94% identical in amino acid sequence, and while delta2 crystallin is the duck orthologue of argininosuccinate lyase (ASL) and catalyzes the reversible breakdown of argininosuccinate to arginine and fumarate, the delta1 isoform is enzymatically inactive. The crystal structures of wild type duck delta1 and delta2 crystallin have been solved at 2.2 and 2.3 A resolution, respectively, and the refinement of the turkey delta1 crystallin has been completed. These structures have been compared with two mutant duck delta2 crystallin structures. Conformational changes were observed in two regions of the N-terminal domain with intraspecies differences between the active and inactive isoforms localized to residues 23-32 and both intra- and interspecies differences localized to the loop of residues 74-89. As the residues implicated in the catalytic mechanism of delta2/ASL are all conserved in delta1, the amino acid substitutions in these two regions are hypothesized to be critical for substrate binding. A sulfate anion was found in the active site of duck delta1 crystallin. This anion, which appears to mimic the fumarate moiety of the argininosuccinate substrate, induces a rigid body movement in domain 3 and a conformational change in the loop of residues 280-290, which together would sequester the substrate from the solvent. The duck delta1 crystallin structure suggests that Ser 281, a residue strictly conserved in all members of the superfamily, could be the catalytic acid in the delta2 crystallin/ASL enzymatic mechanism.

PubMed: 11258884
DOI: 10.1021/bi002272k

Experimental method

X-RAY DIFFRACTION (2.5 Å)