Simulated annealing hydrogen bonds

The structural modeling of PG and PLV with the anti-parallel p-sheet form is carried out by the hybrid distance geometry-dynamic simulated annealing method115 as contained in the X-PLOR 3.1 program.116 For structural calculations, the proton-proton distance restraints and the torsion angle restraints ( =—139° and v /=135°) are derived from reference data by Wiithrich et al.ni Hydrogen-bond distance restraints are used for the N and atoms (2.7-3.3 A) in the secondary structure.118 120 The reference data of intra- and intermolecular proton-proton distances are shown in Fig. 19. 

In the approach of Chin et al., the simulated annealing method was employed on molecules that tend to form hydrogen-bonded tapes (Schwiebert et al. 1995), thus providing a well-defined (but necessarily limited) starting model for the subsequent trial structures. 

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