Structural highlights
Publication Abstract from PubMedHere, we combine the use of host screening, protein crystallography and QM/MM molecular dynamics simulations to investigate how the protein structure affects iminium catalysis by biotinylated secondary amines in a model 1,4 conjugate addition reaction. Monomeric streptavidin (M-Sav) lacks a quaternary structure and the solvent-exposed reaction site resulted in poor product conversion in the model reaction with low enantio- and regioselectivities. These parameters were much improved when the tetrameric host T-Sav was used; indeed, residues at the symmetrical subunit interface were proven to be critical for catalysis through a mutagenesis study. The use of QM/MM simulations and the asymmetric dimeric variant D-Sav revealed that both Lys121 residues which are located in the hosting and neighboring subunits play a critical role in controlling the stereoselectivity and reactivity. Lastly, the D-Sav template, though providing a lower conversion than that of the symmetric tetrameric counterpart, is likely a better starting point for future protein engineering because each surrounding residue within the asymmetric scaffold can be refined for secondary amine catalysis. The role of streptavidin and its variants in catalysis by biotinylated secondary amines.,Nodling AR, Santi N, Castillo R, Lipka-Lloyd M, Jin Y, Morrill LC, Swiderek K, Moliner V, Luk LYP Org Biomol Chem. 2021 Dec 8;19(47):10424-10431. doi: 10.1039/d1ob01947c. PMID:34825690[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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