Table of Contents

## Name

obfit -- superimpose two molecules based on a pattern

## Synopsis

obfit SMARTS-pattern fixed-file outfile

## Description

Superimpose two molecules using a quaternion fit. The atoms used to fit the two molecules are defined by the SMARTS pattern given by the user. It is useful to align congeneric series of molecules on a common structural scaffold for 3D-QSAR studies. It can also be useful for displaying the results of conformational generation.

Any molecules matching the supplied SMARTS pattern will be rotated and translated to provide the smallest possible RMSD between the matching regions. If a molecule does not match the SMARTS pattern, it will be output with no transformation.

## Examples

Align all the molecules in ‘testmv.sdf’ on a single molecule of ‘testref.sdf’ by superimposing them on its N-methylpiperidyl portion (and outputting a new SD file to the standard output):

    obfit '[nh]1c2c(=O)n(C)c(=O)n(C)c2cc1' testref.sdf testmv.sdf

## See Also

babel(1) , obchiral(1) , obfit(1) , obgrep(1) , obrotate(1) .

The web pages for Open Babel can be found at: <http://openbabel.org/>

A guide for constructing SMARTS patterns can be found at: <http://www.daylight.com/dayhtml/doc/theory/theory.smarts.html>

## Authors

The obfit program was contributed by Fabien Fontaine

Open Babel is developed by a cast of many, including currrent maintainers Geoff Hutchison, Chris Morley, Michael Banck, and innumerable others who have contributed fixes and additions. For more contributors to Open Babel, see <http://openbabel.org/wiki/THANKS>

## Copyright

Copyright (C) 1998-2001 by OpenEye Scientific Software, Inc.
Some portions Copyright (C) 2001-2007 by Geoffrey R. Hutchison and other contributors.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Table of Contents

- Name
- Synopsis
- Description
- Examples
- See Also
- Authors
- Copyright