SABBAC v1.2: Structural Alphabet based protein Backbone Builder from Alpha Carbon trace.

Summary: SABBAC is an on-line service devoted to protein backbone reconstruction from alpha-carbon trace. It is based on the assembly of fragments issued from library of reduced size, resulting from the encoding of the protein trace in an HMM-derived structural alphabet [1, 2]. The assembly of the fragments is achieved by a greedy algorithm [3, 4], using an energy based scoring inspired from the OPEP force field [5]. Alpha-carbon coordinates remain unaffected. SABBAC simply positions the missing backbone atoms, no further refinement is performed. From our tests, SABBAC performs equal or better than other similar online approach and is robust to deviations on the alpha-carbon coordinates. It can be accessed at

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v1.2 (September 2006): Systematic use of fast energy calculation. Now accepts large files. Slightly improved results.