Protein Crystallography (PX)

Postgraduate Certificate

PX Syllabus

Section 1	Section 2	Section 3	Section 4	Section 5	Section 6	Section 7	Section 8
Section 9	Section 10	Section 11	Section 12	Section 13	Section 14	Section 15	Section 16

Section 12 - Phase Improvement by Density Modification

Introduction
Background

Noise and Resolution of Electron Density Maps
Phase Refinement/Extension
Flowchart of Density Modification
Flowchart of Density Modification and Refinement
Phase Combination

Steps and Strategy

Solvent Content of Protein Crystals
Modification Functions

Positivity and Boundedness
Solvent Flattening
Histogram Matching
Sayre's Equation
Skeletonisation and Map Continuity
Solvent Flipping and Density Truncation
Non-Crystallographic Symmetry (NCS) Averaging
Multiple-Crystal Averaging
Use of a Partial Model

Programs