Experimental phasing with vanadium and application to nucleotide-binding membrane proteins

Title	Experimental phasing with vanadium and application to nucleotide-binding membrane proteins
Authors	Kamel El Omari, Nada Mohamad, Kiran Bountra, Ramona Duman, Maria Romano, Katja Schlegel, Hok-Sau Kwong, Vitaliy Mykhaylyk, Claus Olesen, Jesper Vuust Moller, Maike Bublitz, Konstantinos Beis, Armin Wagner
Magazine	IUCrJ
Date	10/14/2020
DOI	10.1107/S2052252520012312
Introduction	Determining the structure of both soluble and membrane proteins is often complicated by the crystallographic phase problem, especially without a similar homologous structure. While experimental phasing is preferred for new structures, it traditionally demands heavy-atom derivatisation, which is challenging and lengthy. This paper introduces a new, swift method for obtaining experimental phases for protein structure determination through vanadium phasing. Vanadate, a transition-state analogue of phosphoryl-transfer reactions, specifically binds to the active site of many enzymes involved in this process. The technique's effectiveness was confirmed by determining the structures of three protein-vanadium complexes, including two integral membrane proteins: rabbit sarcoplasmic reticulum Ca2+-ATPase, the ATP-binding cassette transporter McjD from Escherichia coli, and the soluble enzyme RNAse A from Bos taurus. This method succeeded even at low resolution and despite significant data anisotropy. Applicable to numerous proteins across six of the seven Enzyme Commission classes, it depends solely on the protein's specific chemistry and requires no modifications, enhancing the phasing toolkit. Beyond its phasing capabilities, the protein-vanadium complexes provide detailed insights into the reaction mechanisms of the studied proteins.
Quote	Kamel El Omari, Nada Mohamad and Kiran Bountra et al. Experimental phasing with vanadium and application to nucleotide-binding membrane proteins. IUCrJ. 2020. DOI: 10.1107/S2052252520012312
Element	Vanadium (V)
Materials	Chemical Compounds
Topics	Biomedical Materials
Industry	Research & Laboratory