Protein Packing Interactions and Polymorphy of Chorismate Lyase From E. Coli

Published

November 1, 2001

Author(s)

David T. Gallagher

Abstract

The enzyme chorismate lyase from E. coli crystallizes in three well characterized polymorphs in identical conditions. Wild-type enzyme tends to aggregate, even in the presence of reducing agent, and yields monoclinic crystals that grow in intricate clusters. Protein aggregation was largely eliminated by mutating the protein's two cysteines to serines. The double mutant retains full enzymatic activity and grows singly in two new forms: triclinic and orthorhombic. The triclinic crystals diffract to 0.9 resolution. A single-cysteine mutant that crystallizes in the orthorhombic form was used to determine the structure, enabling examination of the packing interactions at 2.0 resolution or better in all three forms. A novel system for labeling contacts is proposed, and relations between packing patterns and crystal properties are discussed. Diffraction resolution is found to correlate with coordination number and with the root-mean-square deviation from mean extent of the contacts. Implications for contact energies are considered.

Citation

Journal of Crystal Growth

Volume

232

Issue

No. 1-4

Pub Type

Journals

Keywords

contacts, crystal forms, packing, protein crystal growth, site-directed mutagenesis

Citation

Gallagher, D. (2001), Protein Packing Interactions and Polymorphy of Chorismate Lyase From E. Coli, Journal of Crystal Growth (Accessed December 30, 2024)