Biology: Introduction to Protein Interactions

Biology: Introduction to Protein Interactions

  • Submitted By: nisha1988
  • Date Submitted: 02/10/2009 3:41 AM
  • Category: Science
  • Words: 251
  • Page: 2
  • Views: 438

Most proteins in a living cell interact in order to fulfil their
function. Protein interactions occur through the formation of
complexes, either transient or more long lasting, as a result of a
balance between different molecular properties: sequence, shape,
charge distribution, entropy and dynamics. Proteins often interact
through multiple components, with examples like the replisome,
RNA polymerases, the spliceosome, the ribosome, chaperonins
and the various complexes formed along signal transduction
pathways and during enzyme catalysis and inhibition. Knowledge
of protein interactions is sometimes crucial in elucidating their
functional roles. 3D structures of protein complexes have been the
basis for detailed understanding of protein function; however, it is
much more technically demanding to determine the structure of a
complex as opposed to solving a structure of a single protein or
even a fragment of the whole protein—a protein domain. This is
the reason why in the current release of the Protein Data Bank
(http://www.pdb.org) [1], 3D structures of protein complexes are
poorly represented. In addition, the number of protein sequences
deposited in the UniprotKB/Swiss-Prot database (http://www.
uniprot.org) [2] outstrips the number of known 3D structures by
around 7 times—a fact that further demonstrates the restricted
effective size of the structural sample set available for studying
protein interactions. On the other hand, experimental methods for
detection of protein interaction residues from proteins without a
known 3D structure are based on mutation and deletion studies.
These methods are expensive, laborious and, most importantly,
poorly applicable on a large scale.

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