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[ccp4bb]: Q: negative B values in mlphare

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I'm currently refining my heavy atom parameters with mlphare, and I
consistently get negative B values, together with high occupancies
(about 2-3). This occurs whether I use SIRAS or a SAD. Derivative is 2.4
A, multiplicity of 6, Rsym about 5%, 99% of anomalous pair recorded,
with nice peaks in the anomalous patterson (not in the difference
though...). Native 2.2 A, multiplicity of 3, Rsym 3.4. When using sharp
for refinement, B values go down to 5 (minimal value accepted), with
occupancies about 1.

Any ideas what might be the problems ?

thanks for your help


Laurent Maveyraud               
Groupe de Cristallographie Biologique  -  IPBS-CNRS

205, route de Narbonne       	 Tel (+33) 05 61 17 54 35
31077 TOULOUSE CEDEX        	 Fax (+33) 05 61 17 54 48
France                       	 mailto:laurent.maveyraud@ipbs.fr