Data Item _phasing_MIR_der_refln.HL_A_iso


Item name
Category name
Attribute name
Required in PDB entries
Used in currrent PDB entries

Item Description

The isomorphous Hendrickson-Lattman coefficient Aiso for this reflection for this derivative. -2.0 * (Fpobs2 + Fhcalc2 - Fphobs2) * Fpobs * cos(alphahcalc) Aiso = ----------------------------------------------- E2 E = (Fphobs - Fpobs - Fhcalc)2 for centric reflections = [(Fphobs - Fpobs) * 21/2 - Fhcalc]2 for acentric reflections Fpobs = the observed structure-factor amplitude of the native Fphobs = the observed structure-factor amplitude of the derivative Fhcalc = the calculated structure-factor amplitude from the heavy-atom model alphahcalc = the calculated phase from the heavy-atom model This coefficient appears in the expression for the phase probability of each isomorphous derivative: Pi(alpha) = exp[k + A * cos(alpha) + B * sin(alpha) + C * cos(2 * alpha) + D * sin(2 * alpha)] Ref: Hendrickson, W. A. & Lattman, E. E. (1970). Acta Cryst. B26, 136-143.

Data Type

Data type code
Data type detail
float item types are the subset of numbers that are the floating numbers.
Primitive data type code
Regular expression