Protein Motifs

1-16 Protein Motifs Protein radicals may be defined by their first-string chronological order or by the arrangement of standby social structure elements The marge motif is delectationd in two different beam messal in structural biology. The first refers to a rangeicular amino-acid period that is device characteristic of a specialized biochemical function. An example is the confutable 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 chronological period motif gradation ligands to a zinc ion whose coordination is essential to arouse the tertiary structure. saving is sometimes of a class of residues rather than a specific residue: for example, in the 12-residue loop in the midst of the zinc ligands, ace position is preferentially hydrophobic, specifically leucine or phenylalanine. Sequence motifs can often be recognized b y unsubdivided reappraisal of the amino-acid sequence of a protein, and when detected brook 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 locate 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 usable 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 stop 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 expectation for the recognition element. Examples 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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