Naslov
The secondary structure of apolipoproteins studied by IR-spectroscopy

Autori
Kosović, Marin ; Krilov, Dubravka ; Balarin, Maja ; Gamulin, Ozren ; Brnjas-Kraljević Jasminka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
International Conference and Biophysics Summer School From SolidState To BioPhysics IV / Laslo Forro ; Davor Pavuna - Cavtat, 2008

Skup
From SolidState To BioPhysics IV

Mjesto i datum
Cavtat, Hrvatska, 06.06.2008. - 13.06.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
apolipoproteins; secondary structure; infrared spectroscopy

Sažetak
Lipoproteins are particles in human plasma that have been investigated for the last 40 years because of their active role in atherogenesis. They have the apolar core of cholesteryl esters and triglycerides, and the outer polar monolayer of phospholipids and free cholesterol. One or more apolipoproteins are emerged in the lipid surface of the particle. The apolipoproteins from two types of lipoproteins were studied: apo B-100 from low density lipoprotein (LDL) and apo AI from high density lipoprotein (HDL). The aim of this study was to analyse the amide I band in the spectra of different classes of lipoproteins in order to compare the obtained results with the known data about the secondary structure of apolipoproteins. Lipoproteins were isolated from the human plasma by ultracentrifugation and prior to measurements samples were dried by nitrogen flow to obtain thin films. Amid I band (1700-1600 cm-1) was investigated to examine secondary structure of the apolipoproteins. Amid I band contains several overlapping component bands which appear as a result of peptide-bond vibrations in different secondary structures. To decompose the amid I band into the individual components, curve fitting analysis was performed, together with techniques for band narrowing such as Fourier self deconvolution and derivative spectroscopy. The relative percentage of different apolipoprotein structures was calculated from the surface area under each component band. The component analyses showed that amide I band of apo AI contains predominantly bands of alfa helix while that of apo B-100 contains significant proportion of several beta structures. These findings are in agreement with the detailed knowledge about the apolipoprotein structures. Therefore, IR-spectroscopy could be applied in the study of structural changes in lipoproteins induced by external agents.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Biologija

POVEZANOST RADA