5ldf
Maltose binding protein genetically fused to dodecameric glutamine synthetaseMaltose binding protein genetically fused to dodecameric glutamine synthetase
Structural highlights
Function[MALE_ECO57] Involved in the high-affinity maltose membrane transport system MalEFGK. Initial receptor for the active transport of and chemotaxis toward maltooligosaccharides (By similarity). Publication Abstract from PubMedRecent technical advances have revolutionized the field of cryo-electron microscopy (cryo-EM). However, most monomeric proteins remain too small (<100 kDa) for cryo-EM analysis. To overcome this limitation, we explored a strategy whereby a monomeric target protein is genetically fused to a homo-oligomeric scaffold protein and the junction optimized to allow the target to adopt the scaffold symmetry, thereby generating a chimeric particle suitable for cryo-EM. To demonstrate the concept, we fused maltose-binding protein (MBP), a 40 kDa monomer, to glutamine synthetase, a dodecamer formed by two hexameric rings. Chimeric constructs with different junction lengths were screened by biophysical analysis and negative-stain EM. The optimal construct yielded a cryo-EM reconstruction that revealed the MBP structure at sub-nanometre resolution. These findings illustrate the feasibility of using homo-oligomeric scaffolds to enable cryo-EM analysis of monomeric proteins, paving the way for applying this strategy to challenging structures resistant to crystallographic and NMR analysis. Fusion to a homo-oligomeric scaffold allows cryo-EM analysis of a small protein.,Coscia F, Estrozi LF, Hans F, Malet H, Noirclerc-Savoye M, Schoehn G, Petosa C Sci Rep. 2016 Aug 3;6:30909. doi: 10.1038/srep30909. PMID:27485862[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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