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1.History

The Rossmann fold, or rather the Rao-Rossmann fold, is a protein structural motif found in proteins that bind nucleotides, such as enzyme cofactors FAD, NAD, and NADP+ .  Although it was never defined, the term fold was coined in 1973 by Rao and Rossmann in relation to nucleotide-binding proteins.The Rossmann fold was explained by Dr. Michael Rossmann and coworkers in 1974. They described that this folding was responsible for the binding of dinucleotide coenzymes in different proteins. The motif is named for Michael Rossmann, who first pointed out that this is a frequently occurring motif in nucleotide binding proteins, such as dehydrogenases.[2] In 1989, Israel Hanukoglu from the Weizmann Institute of Science discovered that the consensus sequence for NADPbinding site in some enzymes that utilize NADP+differs from the NADbinding motif.[3] This discovery was used to re-engineer coenzyme specificities of enzymes.[4]

2.Structure

Through the analysis of four NADH-binding enzymes, it was found that in all four enzymes the nucleotide co-enzyme entailed the same conformation and orientation with respect to the polypeptide chain. After the finding of Rossmann fold, it has been identified in numerous enzymes that utilize the dinucleotide co-enzymes NADH, NADPH and FADH2.  The structure is composed of up to seven mostly parallel beta strands. The first two strands are connected by an α- helix.

3.Function

The Rossmann fold is a commonly distributed super-secondary structures. It entails a series of alternating beta strand and alpha helical segments. The most conserved segment of Rossman folds is the primary beta-alpha-beta fold. Since this segment is in contact with the ADP portion of dinucleotides such as FAD, NAD and NADP it is also called as an "ADP-binding beta-beta fold". Certain Rossmann fold proteins include only one copy of the beta-alpha-beta-alpha-beta structure, with additional beta-strands that form hydrogen-bonds with the previous one. One of the other differences in Rossmann folds in proteins has to do with enzyme-specificity toward the co-enzyme. The structures of Rosmann fold segments between additional strands vary greatly and may be composed of a variety of structures such as multiple short helices or coils. 

Dcinthiya (talk) 08:08, 8 November 2017 (UTC)