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 language | English |
|---|---|
| Pages (from-to) | 3268-3274 |
| Number of pages | 7 |
| Journal | Langmuir |
| Volume | 26 |
| Issue number | 5 |
| DOIs | |
| State | Published - Mar 2 2010 |
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ASJC Scopus subject areas
- Electrochemistry
- Condensed Matter Physics
- Surfaces and Interfaces
- Materials Science(all)
- Spectroscopy
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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 journal › Article
}
TY - JOUR
T1 - Human cardiac troponin I
T2 - A langmuir monolayer study
AU - Orbulescu, Jhony
AU - Micic, Miodrag
AU - Ensor, Mark
AU - Trajkovic, Sanja
AU - Daunert, Sylvia
AU - Leblanc, Roger
PY - 2010/3/2
Y1 - 2010/3/2
N2 - 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.
AB - 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.
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U2 - 10.1021/la903033x
DO - 10.1021/la903033x
M3 - Article
VL - 26
SP - 3268
EP - 3274
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 5
ER -