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A topological description of hubs in amino Acid interaction networks.

Gaci O - Adv Bioinformatics (2010)

Bottom Line: Once we have compared this type of graphs to the general model of scale-free networks, we analyze the existence of nodes which highly interact, the hubs.We describe these nodes taking into account their position in the primary structure to study their apparition frequency in the folded proteins.Finally, we observe that their interaction level is a consequence of the general rules which govern the folding process.

View Article: PubMed Central - PubMed

Affiliation: Le Havre University, LITIS EA 4108, BP 540, 76058 Le Havre, France.

ABSTRACT
We represent proteins by amino acid interaction networks. This is a graph whose vertices are the proteins amino acids and whose edges are the interactions between them. Once we have compared this type of graphs to the general model of scale-free networks, we analyze the existence of nodes which highly interact, the hubs. We describe these nodes taking into account their position in the primary structure to study their apparition frequency in the folded proteins. Finally, we observe that their interaction level is a consequence of the general rules which govern the folding process.

No MeSH data available.


Protein 1DTP (a) and its SSE-IN (b). From a pdb file, a parser we have developed produces a new file which corresponds to the SSE-IN graph displayed by the GraphStream library [1].
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fig1: Protein 1DTP (a) and its SSE-IN (b). From a pdb file, a parser we have developed produces a new file which corresponds to the SSE-IN graph displayed by the GraphStream library [1].

Mentions: Consider a graph with N vertices (each vertex corresponds to an amino acid) and the contact map matrix as incidence matrix. It is called contact map graph. The contact map graph is an abstract description of the protein structure taking into account only the interactions between the amino acids. Now let us consider the subgraph induced by the set of amino acids participating in SSE. We call this graph SSE interaction network (SSE-IN) and this is the object we study in the present paper. The reason of ignoring the amino acids not participating in SSE is simple. Evolution tends to preserve the structural core of proteins composed from SSE. On the other hand, the loops (regions between SSE) are not so important to the structure and hence, are subject to more mutations. That is why homologous proteins tend to have relatively preserved structural cores and variable loop regions. Thus, the structure determining interactions are those between amino acids belonging to the same SSE on local level and between different SSEs on global level. Figure 1 gives an example of a protein and its SSE-IN.


A topological description of hubs in amino Acid interaction networks.

Gaci O - Adv Bioinformatics (2010)

Protein 1DTP (a) and its SSE-IN (b). From a pdb file, a parser we have developed produces a new file which corresponds to the SSE-IN graph displayed by the GraphStream library [1].
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2877201&req=5

fig1: Protein 1DTP (a) and its SSE-IN (b). From a pdb file, a parser we have developed produces a new file which corresponds to the SSE-IN graph displayed by the GraphStream library [1].
Mentions: Consider a graph with N vertices (each vertex corresponds to an amino acid) and the contact map matrix as incidence matrix. It is called contact map graph. The contact map graph is an abstract description of the protein structure taking into account only the interactions between the amino acids. Now let us consider the subgraph induced by the set of amino acids participating in SSE. We call this graph SSE interaction network (SSE-IN) and this is the object we study in the present paper. The reason of ignoring the amino acids not participating in SSE is simple. Evolution tends to preserve the structural core of proteins composed from SSE. On the other hand, the loops (regions between SSE) are not so important to the structure and hence, are subject to more mutations. That is why homologous proteins tend to have relatively preserved structural cores and variable loop regions. Thus, the structure determining interactions are those between amino acids belonging to the same SSE on local level and between different SSEs on global level. Figure 1 gives an example of a protein and its SSE-IN.

Bottom Line: Once we have compared this type of graphs to the general model of scale-free networks, we analyze the existence of nodes which highly interact, the hubs.We describe these nodes taking into account their position in the primary structure to study their apparition frequency in the folded proteins.Finally, we observe that their interaction level is a consequence of the general rules which govern the folding process.

View Article: PubMed Central - PubMed

Affiliation: Le Havre University, LITIS EA 4108, BP 540, 76058 Le Havre, France.

ABSTRACT
We represent proteins by amino acid interaction networks. This is a graph whose vertices are the proteins amino acids and whose edges are the interactions between them. Once we have compared this type of graphs to the general model of scale-free networks, we analyze the existence of nodes which highly interact, the hubs. We describe these nodes taking into account their position in the primary structure to study their apparition frequency in the folded proteins. Finally, we observe that their interaction level is a consequence of the general rules which govern the folding process.

No MeSH data available.