Rossmann fold: Difference between revisions

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Noted that the beta strands in Rossmann folds are generally all parallel.
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Note: This entry on the Rossmann fold has been published in Biochem. Mol. Biol. Educ.<ref>PMID:25704928</ref>. Please cite it as Biochem. Mol. Biol. Educ. 43:206-209, 2015.
Note: This entry on the Rossmann fold has been published in Biochem. Mol. Biol. Educ.<ref name="Hanukoglu-2015">PMID:25704928</ref>. Please cite it as Biochem. Mol. Biol. Educ. 43:206-209, 2015.


The Rossmann fold is a super-secondary structure that is characterized by an alternating motif of beta-strand-alpha helix-beta strand secondary structures. Hence this fold is also called a &beta;&alpha;&beta; fold. The &beta;-strands participate in the formation of a &beta;-sheet.  The &beta;&alpha;&beta; fold structure is commonly observed in enzymes that have dinucleotide coenzymes, such as FAD, NAD and NADP.  
The Rossmann fold is a super-secondary structure that is characterized by an alternating motif of beta-strand-alpha helix-beta strand secondary structures. Hence this fold is also called a &beta;&alpha;&beta; fold. The &beta;-strands participate in the formation of a &beta;-sheet.  The &beta;&alpha;&beta; fold structure is commonly observed in enzymes that have dinucleotide coenzymes, such as FAD, NAD and NADP.  
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[[Image:3-phosphoglycerate_dehydrogenase-2P9E-sheet.png|400px|right|thumb| Fig. 5. 3-phosphoglycerate dehydrogenase ([[2p9e]]) beta sheet in the NAD binding domain. The two beta-strands that form the core of the Rossmann fold are marked in dark-blue ( <span style="color:MediumBlue">&#9608;&#9608;</span> )color.]]
[[Image:3-phosphoglycerate_dehydrogenase-2P9E-sheet.png|400px|right|thumb| Fig. 5. 3-phosphoglycerate dehydrogenase ([[2p9e]]) beta sheet in the NAD binding domain. The two beta-strands that form the core of the Rossmann fold are marked in dark-blue ( <span style="color:MediumBlue">&#9608;&#9608;</span> )color.]]
As seen in the above example of ferredoxin reductase the &beta;-sheet that is in the nucleotide domain may have more than two strands. In many (but not all) proteins with &beta;&alpha;&beta; fold, the &beta;-strands may be part of a larger &beta;-sheet with up to seven &beta;-strands. Figure 5 shows five strands forming a &beta;-sheet in phosphoglycerate dehydrogenase ([[2p9e]]). Note that the segment connecting the second strand to the third is in coiled confirmation and not helical. Whereas the subsequent connections between strands include &alpha;-helix segments.
As seen in the above example of ferredoxin reductase the &beta;-sheet that is in the nucleotide domain may have more than two strands. In many (but not all) proteins with &beta;&alpha;&beta; fold, the &beta;-strands may be part of a larger &beta;-sheet with up to seven &beta;-strands. Figure 5 shows five strands forming a &beta;-sheet in phosphoglycerate dehydrogenase ([[2p9e]]). Note that the segment connecting the second strand to the third is in coiled confirmation and not helical. Whereas the subsequent connections between strands include &alpha;-helix segments.
As seen in the example in Fig. 5, the direction of the strands are all parallel. This represents a general trend in Rossmann folds. However in some Rossmann folds there may be some strands in anti-parallel direction.<ref name="Hanukoglu-2015" />


==Evolutionary origin of the &beta;&alpha;&beta; fold ==
==Evolutionary origin of the &beta;&alpha;&beta; fold ==