Protein Motifs

1-16 Protein Motifs Protein radicals may be defined by their mappingicular chronological order or by the arrangement of standby body structure elements The marge motif is delectationd in two different send out messal in structural biology. The first refers to a particular amino-acid epoch that is trace of a specialized biochemical function. An example is the fishy zinc finger motif, CXX(XX)CXXXXXXXXXXXXHXXXH, which is open up in a widely varying family of DNA- supporting proteins (Figure 1-49). The conserved cysteine and histidine residues in this successiveness motif gradation ligands to a zinc ion whose coordination is essential to change the tertiary structure. saving is sometimes of a class of residues preferably than a specific residue: for example, in the 12-residue loop amongst the zinc ligands, ace position is preferentially hydrophobic, specifically leucine or phenylalanine. Sequence motifs can often be recognized by simple(a) reappraisal of the amino-acid taking over of a protein, and when detected put forward strong register for biochemical function. The protease from the human immunodeficiency computer virus was first place as an aspartyl protease because a characteristic sequence motif for such proteases was recognized in its primary structure. The second, equally common, use of the term motif refers to a differentiate of contiguous secondary structure elements that either have a particular structural significance or define a portion of an independently folded vault of heaven. Along with the operational sequence motifs, the former are cognise generally as functional motifs. An example is the helix-turn-helix motif found in many DNA-binding proteins (Figure 1-50). This simple structural motif allow for not exist as a stably folded cosmos if expressed separately from the repose of its protein context, but when it can be detected in a protein that is already thought to bind nucleic acids, it is a likely expe ctation for the recognition element. Example! s of structural motifs that gift a large part of a stably folded domain include...If you want to get a full essay, order it on our website: OrderCustomPaper.com

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