Estimating the twist of beta-strands embedded within a regular parallel beta-barrel structure.
The parallel beta-barrel is a recurrent structural motif found in a large variety of different enzymes belonging to the family of alpha/beta-proteins. It has been shown previously that the hyperboloid can be considered as a scaffold describing the parallel beta-barrel structure. To assess restraints on beta-strand twist imposed by a given scaffold geometry, the notion of scaffold twist, Ts, is introduced. From Ts, the beta-strand twist (Tw beta) expected for a given scaffold geometry can be derived and it is verified that this computed twist can be used to identify beta-barrels characterized by good hydrogen bonding. It is noted that Tw beta is only slightly affected for beta-barrels differing in the number (N) of beta-strands, suggesting that restraints on main-chain conformation of beta-strands are not likely to account for the N = 8 invariability observed in natural parallel beta-barrels thereby strengthening previous work rationalizing this constancy.
Lasters
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Plant Genetic Systems, Gent, Belgium.
D004798:Enzymes / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*
D004798:Enzymes; D011506:Proteins