id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-321275-7haq0e38	Renzi, Fabiana	Large-scale purification and crystallization of the endoribonuclease XendoU: troubleshooting with His-tagged proteins	2006-02-28		.txt	text/plain	1971	101	58	The tendency of the recombinant enzyme to aggregate could be reversed upon the addition of chelating agents (EDTA, imidazole): aggregation is a potential drawback when purifying and crystallizing His-tagged proteins, which are widely used, especially in high-throughput structural studies. Subsequent screening resulted in the growth of crystals (300 Â 300 Â 300 mm) in 40% (NH 4 ) 2 SO 4 , 0.2 M sodium citrate pH 6 at 293 K which belonged to space group P3 1 21 but diffracted poorly; the resolution was improved by cocrystallization with 50 mM uridine 5 0 -monophosphate (5 0 -UMP), which may bind to the active site, possibly inducing the stabilization of flexible regions (Fig. 2a) . Large-scale expression of His-tagged XendoU resulted in soluble protein that was heterogeneously aggregated, a condition that affects crystallization (Wilson, 2003) .	./cache/cord-321275-7haq0e38.txt	./txt/cord-321275-7haq0e38.txt