Hi Ed, Chapter 18.3 of international tables vol F includes values designated EH99 which are from a more recent CSD release than the original 1991 Engh & Huber paper. R. A. Engh and R. Huber. Structure quality and target parameters. International Tables for Crystallography (2012). Vol. F, ch. 18.3, pp. 474-484 doi: 10.1107/97809553602060000857 http://it.iucr.org/Fb/ch18o3v0001/
Also, the Buster groups' Grade server provides dynamic use of the CSD database to derive restraints. http://grade.globalphasing.org And the PURY restraint database has restraints derived from recent CSD releases. I belive it requires a current CSD license is required for use. http://pury.ijs.si/ Regards, Mitch -----Original Message----- From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of Ed Pozharski Sent: Monday, January 14, 2013 9:55 AM To: [email protected] Subject: [ccp4bb] engh huber To what extent "modern" geometric restraints have been upgraded over original Engh&Huber? And where I can find a consensus set of values (with variances)? For example, Fisher et al., Acta D68:800 discusses how histidine angles change with protonation, and refers to Engh&Huber when it says that ND1-CE1-NE2 goes from 111.2 to 107.5 when histidine acquires positive charge (Fig.6). But angle table (Table 3) in original Engh&Huber from 1991 does not have any 107.5 value and seems to suggest that the numbers should rather be 111.7+-1.3 and 108.4+-1.0, respectively. I understand that these values are derived from structural databases and thus can be frequently updated. Is there some resource where "most current" values would be listed? Cheers, Ed. -- After much deep and profound brain things inside my head, I have decided to thank you for bringing peace to our home. Julian, King of Lemurs
