Knowledge-Based B-Factor Restraints for the Refinement of Proteins

A new type of restraint for the B factors of atoms in low- to-moderate resolution models of proteins is proposed. This restraint incorporates the knowledge that the B factors of two atoms bonded to each other may be systemically different. In addition, some bonded pairs of atoms will be more consistent from structure to structure than others. With the use of B-factor restraints of this type, it is possible to construct models whose B factors are consistent with accurately known protein structures, even though only low-resolution crystallographic data are available.