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Updated: Jun 23, 2026

X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
X-ray crystal analysis of a TASP: structural insights of a cavitein dimer
Jon O Freeman1, Woo Cheol Lee, Michael E P Murphy
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1.
Abstract:
Cavitein Q4 is a template assembled synthetic protein designed for X-ray crystallographic analysis. It is based on a previous monomeric helical bundle cavitein (N1GG) that consists of four identical parallel helical peptides. Crystals that were grown in the presence of bromide ions were used to solve the initial phases via single-wavelength anomalous dispersion (SAD). A 1.4 A resolution data set was then refined starting with the SAD phases to provide the crystal structure of cavitein Q4. The crystal structure revealed cavitein Q4 as an asymmetric dimer, although the cavitein appears to be largely monomeric in solution. A comparative analysis is carried out to discern any intrinsic differences between Q4 and its parent cavitein N1GG. We present herein the first X-ray crystal structure of a TASP system and relate this structure to the solution data for both Q4 and its parent N1GG.
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