Experimental phasing: Difference between revisions

* [http://www.globalphasing.com/sharp/ SHARP]

SHARP was the first "product" of [http://www.globalphasing.com/ Global Phasing], in the mid '90s. It was a spectacular improvement over existing methods and has been described in [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B7CV2-4B432JN-DY&_user=3208271&_coverDate=12%2F31%2F1997&_alid=865881649&_rdoc=5&_fmt=high&_orig=search&_cdi=18066&_sort=d&_docanchor=&view=c&_ct=5&_acct=C000047720&_version=1&_urlVersion=0&_userid=3208271&md5=1a457e261908cb35b80cd39fc7c7cd6d Maximum-likelihood heavy-atom parameter refinement for multiple isomorphous replacement and multiwavelength anomalous diffraction methods].

SHARP has been regularly improved since then, and the legendary 'week-long runs' now complete in a few minutes. Much has been argued about how SHARP implements Maximum Likelihood, and Phaser and BP3 claim to do better in SAD cases. SHARP does do really well for SAD phasing, but the main advantage still is the ability to describe very complicated experiments, involving multiple wavelengths, various crystals of the same derivative and various derivatives (all with or without anomalous data) in a very appropriate manner. All these can also be done through the autoSHARP pipeline as well. The SHARP interface is web based, excellent on-line help, and very good examples. A CCP4i interface to SHARP is also available.