Bahar I, Atilgan AR, Erman B. Direct evaluation of thermal fluctuations in proteins using a single-parameter harmonic potential.
FOLDING & DESIGN 1997;
2:173-81. [PMID:
9218955 DOI:
10.1016/s1359-0278(97)00024-2]
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Abstract
BACKGROUND
An elastic network model is proposed for the interactions between closely (< or = 7.0 A) located alpha-carbon pairs in folded proteins. A single-parameter harmonic potential is adopted for the fluctuations of residues about their mean positions in the crystal structure. The model is based on writing the Kirchhoff adjacency matrix for a protein defining the proximity of residues in space. The elements of the inverse of the Kirchhoff matrix give directly the auto-correlations or cross-correlations of atomic fluctuations.
RESULTS
The temperature factors of the C alpha atoms of 12 X-ray structures, ranging from a 41 residue subunit to a 633 residue dimer, are accurately predicted. Cross-correlations are also efficiently characterized, in close agreement with results obtained with a normal mode analysis coupled with energy minimization.
CONCLUSIONS
The simple model and method proposed here provide a satisfactory description of the correlations between atomic fluctuations. Furthermore, this is achieved within computation times at least one order of magnitude shorter than commonly used molecular approaches.
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