Index

Protein Data Bank exchange dictionary (pdbx) version 1.0521

_pdbx_refine_component.connect

Definition:

   
      The index of connectivity is the product of the (2Fobs-Fcal) electron 
      density values for the backbone atoms (N, CA and C) divided by the 
      average value for the structure. Low values (less than 1.0) of this 
      index indicate breaks in the backbone electron density which may be 
      due to flexibility of the chain or incorrect tracing.

      connect = [(D(xi)...D(xi))^(1/N)] /<D>_all

      Where:
      D(xi) = (2*Fobs - Fcal)
      <D>_all is the averaged value of density for the structure.
      The product is for N atoms of group.

      Ref: Vaguine, A.A., Richelle, J. & Wodak, S.J. (1999). Acta Cryst. D55,199-205

Type: float

Mandatory item: no

Category: pdbx_refine_component