α-helices on One Side of a β-sheet
High-energy phosphate carrier from the phosphotransferase system of E. coli.
Heat shock protein 90, or Hsp90, is a molecular chaperone that plays an essential role in the folding and activation of a range of client proteins involved in cell cycle regulation and signal transduction in eukaryotic cells.
translucent surface model.
α-helices on Both Sides of a β-sheet
Flavodoxin. The flavodoxin fold is a distinct structural motif consisting of a four-stranded β-sheet and four flanking α-helices. It has been identified in the three-dimensional structures of many proteins. There is, however, little sequence identity between domains with this fold. Note the placement of the helices with respect to the central β-sheet.
α-helices on Both Sides of a β-sheet
Carboxypeptidase A is a protease secreted by the pancreas.
the camera to straight into the active site. The zinc atom (blue-gray) plays an essential role in the mechanism of carboxypeptidase-catalyzed reactions. spacefilled model. We will discuss the mechanism of this enzyme in more detail later.
The framework of this molecule is a mixed β-sheet consisting of eight strands. the β-sheet. How many β-strands are anti-parallel to each other?
Six out of eight α-helices are packed against the central β-sheet.
α-helices on Both Sides of a β-sheet
Caspase-3 complexed to a tetrapeptide inhihitor (CPK). The molecule consists of two identical subunits. Note that the two β-sheets form a single continuous sheet at the subunit interface. spacefill.
Caspases are cysteine proteases with aspartic acid specificity. Members of the caspase family of proteases transmit the events that lead to apoptosis of animal cells. Distinct members of the family are involved in both the initiation and execution phases of cell death, with the initiator caspases being recruited to multicomponent signaling complexes.