Title
"Fluctuograms" reveal the intermittent intra-protein communication in subtilisin Carlsberg and correlate mechanical coupling with co-evolution.
Abstract
The mechanism of intra-protein communication and allosteric coupling is key to understanding the structure-property relationship of protein function. For subtilisin Carlsberg, the Ca2+-binding loop is distal to substrate-binding and active sites, yet the serine protease function depends on Ca2+ binding. The atomic molecular dynamics (MD) simulations of apo and Ca2+-bound subtilisin show similar structures and there is no direct evidence that subtilisin has alternative conformations. To model the intra-protein communication due to Ca2+ binding, we transform the sequential segments of an atomic MD trajectory into separate elastic network models to represent anharmonicity and nonlinearity effectively as the temporal and spatial variation of the mechanical coupling network. In analogy to the spectrogram of sound waves, this transformation is termed the "fluctuogram" of protein dynamics. We illustrate that the Ca2+-bound and apo states of subtilisin have different fluctuograms and that intra-protein communication proceeds intermittently both in space and in time. We found that residues with large mechanical coupling variation due to Ca2+ binding correlate with the reported mutation sites selected by directed evolution for improving the stability of subtilisin and its activity in a non-aqueous environment. Furthermore, we utilize the fluctuograms calculated from MD to capture the highly correlated residues in a multiple sequence alignment. We show that in addition to the magnitude, the variance of coupling strength is also an indicative property for the sequence correlation observed in a statistical coupling analysis. The results of this work illustrate that the mechanical coupling networks calculated from atomic details can be used to correlate with functionally important mutation sites and co-evolution.
Year
DOI
Venue
2011
10.1371/journal.pcbi.1002023
PLOS COMPUTATIONAL BIOLOGY
Keywords
Field
DocType
mutation,directed evolution,spatial variation,active site,binding sites,calcium,sequence alignment,molecular dynamic,protein conformation,molecular dynamics simulation,functional dependency,multiple sequence alignment
Serine protease,Statistical coupling analysis,Subtilisin,Biology,Protein dynamics,Molecular dynamics,Bioinformatics,Multiple sequence alignment,Directed evolution,Protein structure
Journal
Volume
Issue
ISSN
7
3
1553-7358
Citations 
PageRank 
References 
2
0.50
7
Authors
3
Name
Order
Citations
PageRank
Jordi Silvestre-Ryan120.84
Yuchun Lin241.24
Jhih-Wei Chu320.84