title: A Whole-Cell Surface Plasmon Resonance Sensor Based on a Leucine Auxotroph of Escherichia coli Displaying a Gold-Binding Protein: Usefulness for Diagnosis of Maple Syrup Urine Disease.
abstract: We developed a whole-cell surface plasmon resonance (SPR) sensor based on a leucine auxotroph of Escherichia coli displaying a gold-binding protein (GBP) in response to cell growth and applied this sensor to the diagnosis of maple syrup urine disease, which is represented by the elevated leucine level in blood. The leucine auxotroph was genetically engineered to grow displaying GBP in a proportion to the concentration of target amino acid leucine. The GBP expressed on the surface of the auxotrophs directly bound to the golden surface of an SPR chip without the need for any additional treatment or reagents, which consequently produced SPR signals used to determine leucine levels in a test sample. Gold nanoparticles (GNPs) were further applied to the SPR system, which significantly enhanced the signal intensity up to 10-fold by specifically binding to GBP expressed on the cell surface. Finally, the diagnostic utility of our system was demonstrated by its employment in reliably determining different statuses of maple syrup urine disease based on a known cutoff level of leucine. This new approach based on an amino acid-auxotrophic E. coli strain expressing a GBP that binds to an SPR sensor holds great promise for detection of other metabolic diseases of newborn babies including homocystinuria and phenylketonuria, which are also associated with abnormal levels of amino acids.
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.|Food Safety Research Group, Korea Food Research Institute , Baekhyun-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-746, Republic of Korea.
authors.forename: Min-Ah
authors.initials: MA
authors.lastname: Woo
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
authors.forename: Jung Hun
authors.initials: JH
authors.lastname: Park
authors.affiliation: LabGenomics Co., Ltd. , 1571-17 Seocho3-dong, Seocho-gu, Seoul 137-874, Republic of Korea.
authors.forename: Daeyeon
authors.initials: D
authors.lastname: Cho
authors.affiliation: Department of Chemical and Biological Engineering, Korea University , Anam-Dong 5-1, Seongbuk-Gu, Seoul 136-713, Republic of Korea.
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Sim
authors.affiliation: Department of BioNano Technology, Gachon University , 1342 Seongnamdae-ro, Sujeong-gu, Seongnam-si, Gyeonggi-do 461-701, Republic of Korea.
authors.forename: Moon Il
authors.initials: MI
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST , 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
authors.forename: Hyun Gyu
authors.initials: HG
authors.lastname: Park
mesh_terms: D004926:Escherichia coli / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007930:Leucine / Q000032:analysis*; D008375:Maple Syrup Urine Disease / Q000175:diagnosis*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D006046:Gold; D007930:Leucine