There were a number of labs using anomalous dispersion for phasing 40 years
ago. The theory for using it dates from the 60s. And careful experimental
technique allowed the structure solution of several proteins before 1980 using
what would be labeled now as SIRAS. Ron
On Wed, 6 Jun 2012, Dyda wrote:
I suspect that pure MIR (without anomalous) was always a fiction. I doubt that
anyone has ever used it. Heavy atoms always give
an anomalous signal
Phil
I suspect that there was a time when the anomalous signal in data sets was
fictional.
Before the invent of flash freezing, systematic errors due to decay and the need
of scaling together many derivative data sets collected on multiple crystals
could render
weak anomalous signal useless. Therefore MIR was needed. Also, current
hardware/software
produces much better reduced data, so weak signals can become useful.
Fred
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Fred Dyda, Ph.D. Phone:301-402-4496
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