Optical sensing systems based on biomolecular recognition of recombinant proteins

Lyndon L.E. Salins, Vesna Schauer-Vukasinovic, Sylvia Daunert

Research output: Contribution to journalConference articlepeer-review

10 Scopus citations


Site-directed mutagenesis and the associated site-specific fluorescent labeling of proteins can be used to rationally design reagentless fluorescent molecular sensors. The phosphate binding protein (PBP) and calmodulin (CaM) bind to phosphate and calcium in a highly specific manner. These ions induce a hinge motion in the proteins, and the resultant conformational change constitutes the basis of the sensor development. By labeling each protein at a specific site with environment-sensitive fluorescent probes, these conformational changes can be monitored and related to the amount of analyte ion present. In this study, the polymerase chain reaction (PCR) was used to construct mutants of PBP and CaM that have a single cysteine at positions 197 and 109, respectively. Each protein was site-specifically labeled through the sulfhydryl group of the introduced cysteine residue at a single location with an environment-sensitive fluorescent probe. Characterization of the steady-state fluorescence indicated an enhancement of signal intensity upon binding of the analyte ion. Highly sensitive and selective sensing systems for phosphate and calcium were obtained by using this approach.

Original languageEnglish (US)
Pages (from-to)16-24
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Dec 1 1998
Externally publishedYes
EventMethods for Ultrasensitive Detection - San Jose, CA, United States
Duration: Jan 26 1998Jan 28 1998


  • Calcium
  • Calmodulin (CaM)
  • Fluorescence
  • Optical sensing
  • Phosphate
  • Phosphate binding protein (PBP)
  • Site-directed mutagenesis

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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