1JAE

STRUCTURE OF TENEBRIO MOLITOR LARVAL ALPHA-AMYLASE

Summary for 1JAE

• Entry DOI: 10.2210/pdb1jae/pdb
• Descriptor: ALPHA-AMYLASE, CALCIUM ION, CHLORIDE ION, ... (4 entities in total)
• Functional Keywords: glycosidase, alpha-amylase, carbohydrate metabolism, alpha-1, 4-glucan-4-glucanohydrolase, hydrolase
• Biological source: Tenebrio molitor (yellow mealworm)
• Total number of polymer chains: 1
• Total formula weight: 51338.60

Authors

Strobl, S.,Maskos, K.,Betz, M.,Wiegand, G.,Huber, R.,Gomis-Rueth, F.X.,Frank, G.,Glockshuber, R. (deposition date: 1997-09-30, release date: 1998-11-04, Last modification date: 2024-10-23)

Primary citation

Strobl, S.,Maskos, K.,Betz, M.,Wiegand, G.,Huber, R.,Gomis-Ruth, F.X.,Glockshuber, R.
Crystal structure of yellow meal worm alpha-amylase at 1.64 A resolution.
J.Mol.Biol., 278:617-628, 1998

PubMed Abstract: The three-dimensional structure of the alpha-amylase from Tenebrio molitor larvae (TMA) has been determined by molecular replacement techniques using diffraction data of a crystal of space group P212121 (a=51.24 A; b=93.46 A; c=96.95 A). The structure has been refined to a crystallographic R-factor of 17.7% for 58,219 independent reflections in the 7.0 to 1.64 A resolution range, with root-mean-square deviations of 0.008 A for bond lengths and 1.482 degrees for bond angles. The final model comprises all 471 residues of TMA, 261 water molecules, one calcium cation and one chloride anion. The electron density confirms that the N-terminal glutamine residue has undergone a post-transitional modification resulting in a stable 5-oxo-proline residue. The X-ray structure of TMA provides the first three-dimensional model of an insect alpha-amylase. The monomeric enzyme exhibits an elongated shape approximately 75 Ax46 Ax40 A and consists of three distinct domains, in line with models for alpha-amylases from microbial, plant and mammalian origin. However, the structure of TMA reflects in the substrate and inhibitor binding region a remarkable difference from mammalian alpha-amylases: the lack of a highly flexible, glycine-rich loop, which has been proposed to be involved in a "trap-release" mechanism of substrate hydrolysis by mammalian alpha-amylases. The structural differences between alpha-amylases of various origins might explain the specificity of inhibitors directed exclusively against insect alpha-amylases.

PubMed: 9600843
DOI: 10.1006/jmbi.1998.1667

Experimental method

X-RAY DIFFRACTION (1.65 Å)