Affinity tags can reduce merohedral twinning of membrane protein crystals
Journal article, 2008

This work presents a comparison of the crystal packing of three eukaryotic membrane proteins: human aquaporin 1, human aquaporin 5 and a spinach plasma membrane aquaporin. All were purified from expression constructs both with and without affinity tags. With the exception of tagged aquaporin 1, all constructs yielded crystals. Two significant effects of the affinity tags were observed: crystals containing a tag typically diffracted to lower resolution than those from constructs encoding the protein sequence alone and constructs without a tag frequently produced crystals that suffered from merohedral twinning. Twinning is a challenging crystallographic problem that can seriously hinder solution of the structure. Thus, for integral membrane proteins, the addition of an affinity tag may help to disrupt the approximate symmetry of the protein and thereby reduce or avoid merohedral twinning.


Anna Backmark

Chalmers, Chemical and Biological Engineering

Anna Maria Nyblom

Chalmers, Chemical and Biological Engineering, Molecular Imaging

Susanna Törnroth-Horsefield

University of Gothenburg

Urszula Kosinska-Eriksson

University of Gothenburg

Kristina Hedfalk

University of Gothenburg

Karin Lindkvist-Petersson

University of Gothenburg

Richard Neutze

University of Gothenburg

Rob Horsefield

University of Gothenburg

Acta Crystallographica Section D: Biological Crystallography

0907-4449 (ISSN) 1399-0047 (eISSN)

Vol. D64 11 1183-1186

Subject Categories

Biological Sciences

Chemical Sciences



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