There are many cases where people use a structure refined at high
resolution as a starting molecular replacement structure for a closely
related/same protein with a lower resolution data set and get
substantially better R statistics than you would expect for that
resolution. So one factor in the "R factor gap" is many small errors
that are introduced during model building and not recognized and fixed
later due to limited resolution. In a perfect world, refinement would
find the global minimum but in practice all these little errors get
stuck in local minima with distortions in neighboring atoms
compensating for the initial error and thereby hiding their existence. Bart On 10-10-28 11:33 AM, James Holton wrote: It is important to remember that if you have Gaussian-distributed errors and you plot error bars between +1 sigma and -1 sigma (where "sigma" is the rms error), then you expect the "right" curve to miss the error bars about 30% of the time. This is just a property of the Gaussian distribution: you expect a certain small number of the errors to be large. If the curve passes within the bounds of every single one of your error bars, then your error estimates are either too big, or the errors have a non-Gaussian distribution. -- ============================================================================ Bart Hazes (Associate Professor) Dept. of Medical Microbiology & Immunology University of Alberta 1-15 Medical Sciences Building Edmonton, Alberta Canada, T6G 2H7 phone: 1-780-492-0042 fax: 1-780-492-7521 ============================================================================ |
- Re: [ccp4bb] Against Method (R) Ethan Merritt
- Re: [ccp4bb] Against Method (R) Frank von Delft
- Re: [ccp4bb] Against Method (R) Ethan A Merritt
- Re: [ccp4bb] Against Method (R) Ed Pozharski
- Re: [ccp4bb] Against Method (R) George M. Sheldrick
- Re: [ccp4bb] Against Method (R) Jacob Keller
- Re: [ccp4bb] Against Method (R) Ed Pozharski
- Re: [ccp4bb] Against Method (R) George M. Sheldrick
- Re: [ccp4bb] Against Method (R) Jacob Keller
- Re: [ccp4bb] Against Method (R) James Holton
- Re: [ccp4bb] Against Method (R) Bart Hazes
- Re: [ccp4bb] Against Method (R) Jacob Keller
- Re: [ccp4bb] Against Method (R) Ethan Merritt
- Re: [ccp4bb] Against Method (R) Bart Hazes
- Re: [ccp4bb] Against Method (R) Robbie Joosten
- Re: [ccp4bb] Against Method (R) Dirk Kostrewa
- Re: [ccp4bb] Against Method (R) George M. Sheldrick
- Re: [ccp4bb] Against Method (R) Dirk Kostrewa
- Re: [ccp4bb] Against Method (R) Bart Hazes
- Re: [ccp4bb] Against Method (R) Bart Hazes
- Re: [ccp4bb] Against Method (R) James Holton