Protein sequence-structure target proteins

Small tfbiquitin-like modifier represents a family of evolutionary conserved proteins that are distantly related in amino-acid sequence to ubiquitin, but share the same structural folding with ubiquitin proteins. SUMO proteins are covalently conjugated to protein substrates by an isopeptide bond through their carboxyl termini. SUMO addition to lysine residues of target proteins, termed SUMOylation, mediates post-transla-tional modification and requires a set of enzymes that are distinct from those that act on ubiquitin. SUMOylation regulates the activity of a variety of tar get proteins including transcription factors. 

Threading techniques try to match a target sequence on a library of known 3D structures by threading the target sequence over the known coordinates. In this manner, threading tries to predict the 3D structure starting from a given protein sequence. It is sometimes successful when comparisons based on sequences or sequence profiles alone fail due to a too low sequence similarity. 

The maturation of proteins into their final structural state often involves the cleavage or formation (or both) of covalent bonds, a process termed posttranslational modification. Many polypeptides are initially synthesized as larger precursors, called proproteins. The extra polypeptide segments in these proproteins often serve as leader sequences that target a polypeptide... 

One Holy Grail in protein structure is to develop tools that accurately predict three-dimensional structures of proteins from their primary sequence information [58, 59]. Many of the best tools to date only go part of the way by using known three-dimensional structures from proteins which share similar primary sequence to model the possible structures of new proteins. This technology still has a long way to go, but the potential rewards would be enormous, allowing a genome sequence to be translated into targets for therapeutic intervention in si-lico, in relatively short periods of time. 

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