Gert Vriend
EMBL Meyerhofstrasse 1, 6g117, Heidelberg, Germany
The program WHAT IF provides a multitude of tools that can aid with
modeling, drug design, structure description and comparison, mutant
prediction, inverted threading, etc. One of the many tools is automatic
model building by homology from a given alignment with the sequence of
a known structure. The three models submitted for the model building
by homology competition were generated using this fully automatic
method (only a few manual interventions were made, and those are listed
in the submitted file headers).
Given a perfect alignment, this method normally leads to very good
models, although many problems still have to be solved. We routinely
use a set of 25 pairs of structures that can be modeled back and forth.
This dataset has been selected to fulfill the following criteria:
- very few insertions and deletions.
- equally spread over the 35-95% identity range
- not too many co-factors
- equally spread over all known folds
- high quality
During the demonstrations several typical problem cases can be
discussed. The quality of the model will never be better than the
quality of the structure t was based on. Therefore the program WHAT IF
provides extensive structure verification tools. These can be used to
check the starting structures, but also to verify the final models. In
several of the submitted models WHAT IF detected errors in the final
model. I think (we will see it at the meeting...) that these are the
result of poor sequence alignment. This is a different problem from the
one I concentrated on, but it is nice to see that programs can detect
these problems automagically. At the meeting we will see if these error
detection techniques actually work or not. In any event, they can be
discussed during the demonstrations.
P.S. WHAT IF is not a commercial product. It is distributed under
restricted share-ware conditions.
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Last modified on 1-11-95