Human cardiac troponin I

A langmuir monolayer study

Jhony Orbulescu, Miodrag Micic, Mark Ensor, Sanja Trajkovic, Sylvia Daunert, Roger Leblanc

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Human cardiac troponin I (cTnI) is the preferred biomarker in the assessment of myocardial infarction. It is known to interact with troponin C and T to form a trimeric complex. Whereas small amounts are found in the cytoplasm, most of cTnI is in the form of a complex with actin located in myofilaments. To understand these interactions of cTnI better, we first investigated the surface chemistry of cTnI as a Langmuir monolayer spread at the air-water interface. We investigated the optimal conditions for obtaining a stable Langmuir monolayer in terms of changing the ionic strength of the subphase using different concentrations of potassium chloride. Monolayer stability was investigated by compressing the cTnI monolayer to a specific surface pressure and keeping the surface pressure constant while measuring the decrease in the molecular area as a function of time. Aggregation and/or domain formation was investigated by using compression-decompression cycles, in situ UV-vis spectroscopy, Brewster angle microscopy (BAM), and epifluorescence microscopy. To ensure that the secondary structure is maintained, we used infrared reflection-absorption spectroscopy (IRRAS) directly at the air-subphase interface. It was found that cTnI forms a very stable monolayer (after more that 5000 s) that does not aggregate at the air-subphase interface. The cTnI molecules maintain their secondary structure and, on the basis of the low reflectivity observed, using BAM measurements and the low reflection-absorption intensities measured with IRRAS spectroscopy, lie flat on the subphase with the α-helices parallel to the air-subphase interface.

Original languageEnglish
Pages (from-to)3268-3274
Number of pages7
JournalLangmuir
Volume26
Issue number5
DOIs
StatePublished - Mar 2 2010

Fingerprint

Troponin I
monomolecular films
Monolayers
Brewster angle
infrared reflection
air
microscopy
Microscopic examination
absorption spectroscopy
Air
Absorption spectroscopy
myocardial infarction
potassium chlorides
cytoplasm
biomarkers
pressure reduction
Infrared radiation
compressing
helices
spectroscopy

ASJC Scopus subject areas

  • Electrochemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Materials Science(all)
  • Spectroscopy

Cite this

Orbulescu, J., Micic, M., Ensor, M., Trajkovic, S., Daunert, S., & Leblanc, R. (2010). Human cardiac troponin I: A langmuir monolayer study. Langmuir, 26(5), 3268-3274. https://doi.org/10.1021/la903033x

Human cardiac troponin I : A langmuir monolayer study. / Orbulescu, Jhony; Micic, Miodrag; Ensor, Mark; Trajkovic, Sanja; Daunert, Sylvia; Leblanc, Roger.

In: Langmuir, Vol. 26, No. 5, 02.03.2010, p. 3268-3274.

Research output: Contribution to journalArticle

Orbulescu, J, Micic, M, Ensor, M, Trajkovic, S, Daunert, S & Leblanc, R 2010, 'Human cardiac troponin I: A langmuir monolayer study', Langmuir, vol. 26, no. 5, pp. 3268-3274. https://doi.org/10.1021/la903033x
Orbulescu, Jhony ; Micic, Miodrag ; Ensor, Mark ; Trajkovic, Sanja ; Daunert, Sylvia ; Leblanc, Roger. / Human cardiac troponin I : A langmuir monolayer study. In: Langmuir. 2010 ; Vol. 26, No. 5. pp. 3268-3274.
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