title: An intrinsically fluorescent recognition ligand scaffold based on chaperonin protein and semiconductor quantum-dot conjugates.
abstract: Genetic engineering of a novel protein-nanoparticle hybrid system with great potential for biosensing applications and for patterning of various types of nanoparticles is described. The hybrid system is based on a genetically modified chaperonin protein from the hyperthermophilic archaeon Sulfolobus shibatae. This chaperonin is an 18-subunit double ring, which self-assembles in the presence of Mg ions and ATP. Described here is a mutant chaperonin (His-beta-loopless, HBLL) with increased access to the central cavity and His-tags on each subunit extending into the central cavity. This mutant binds water-soluble semiconductor quantum dots, creating a protein-encapsulated fluorescent nanoparticle. The new bioconjugate has high affinity, in the order of strong antibody-antigen interactions, a one-to-one protein-nanoparticle stoichiometry, and high stability. By adding selective binding sites to the solvent-exposed regions of the chaperonin, this protein-nanoparticle bioconjugate becomes a sensor for specific targets.
authors.affiliation: Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Xie
authors.forename: Yi-Fen
authors.initials: YF
authors.lastname: Li
authors.forename: Hiromi K
authors.initials: HK
authors.lastname: Kagawa
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Trent
authors.forename: Kumara
authors.initials: K
authors.lastname: Mudalige
authors.forename: Mircea
authors.initials: M
authors.lastname: Cotlet
authors.forename: Basil I
authors.initials: BI
authors.lastname: Swanson