Improved success of sparse matrix protein crystallization screening with heterogeneous nucleating agents

PLoS One. 2007 Oct 31;2(10):e1091. doi: 10.1371/journal.pone.0001091.

Abstract

Background: Crystallization is a major bottleneck in the process of macromolecular structure determination by X-ray crystallography. Successful crystallization requires the formation of nuclei and their subsequent growth to crystals of suitable size. Crystal growth generally occurs spontaneously in a supersaturated solution as a result of homogenous nucleation. However, in a typical sparse matrix screening experiment, precipitant and protein concentration are not sampled extensively, and supersaturation conditions suitable for nucleation are often missed.

Methodology/principal findings: We tested the effect of nine potential heterogenous nucleating agents on crystallization of ten test proteins in a sparse matrix screen. Several nucleating agents induced crystal formation under conditions where no crystallization occurred in the absence of the nucleating agent. Four nucleating agents: dried seaweed; horse hair; cellulose and hydroxyapatite, had a considerable overall positive effect on crystallization success. This effect was further enhanced when these nucleating agents were used in combination with each other.

Conclusions/significance: Our results suggest that the addition of heterogeneous nucleating agents increases the chances of crystal formation when using sparse matrix screens.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biochemistry / methods
  • Cellulose / chemistry
  • Crystallization
  • Crystallography, X-Ray / methods*
  • Dextrans / chemistry
  • Diffusion
  • Durapatite / chemistry
  • Models, Biological
  • Molecular Structure
  • Protein Denaturation
  • Proteins / chemistry*
  • Silicon Dioxide / chemistry
  • Solubility
  • Titanium / chemistry

Substances

  • Dextrans
  • Proteins
  • titanium dioxide
  • Silicon Dioxide
  • Cellulose
  • sephadex
  • Durapatite
  • Titanium