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Denaturation of type I collagen fibrils is an endothermic process accompanied by a noticeable change in the partial heat capacity.

Abstract：

:Thermal transitions of type I collagen fibrils were investigated by differential scanning calorimetry and spectrophotometry of turbidity within a wide range of external conditions. The advanced microcalorimeter allowed us to carry out the measurements at low concentrations of collagen (0.15-0.3 mg/mL). At these concentrations of collagen and under fibril-forming conditions, the melting curves display two pronounced heat adsorption peaks (at 40 and 55 degreesC). The low-temperature peak was assigned to the melting of monomeric collagen, while the high-temperature peak was assigned to the denaturation of collagen fibrils. It was shown that the denaturation of fibrils, in contrast to the monomeric collagen, is accompanied by a noticeable change in the partial specific heat capacity. Surprisingly, comparison of the collagen calorimetric curves in the fibril-forming and nonforming conditions revealed that DeltaCp of fibril denaturation is caused by a decrease in the Cp of collagen at premelting temperatures. This suggests the existence of an intermediate structural state of collagen in a transparent solution preceding fibril formation. Our study also shows that collagen fibrils formed prior to heating have thermodynamic parameters different from those of fibrils formed and denatured during heating in the calorimeter. Analysis of the data allowed us to determine the denaturation enthalpy of the mature fibrils and to conclude that the enthalpy plays a more important role in fibril stabilization than was previously assumed. The observed large DeltaCp value of fibril denaturation as well as the difference between thermodynamic parameters of the mature and newly formed fibrils is readily explained by the presence of water molecules in the fibril structure.

journal_name

Biochemistry

journal_title

Biochemistry

authors

Tiktopulo EI,Kajava AV

doi

10.1021/bi980360n

subject

Has Abstract

pub_date

1998-06-02 00:00:00

pages

8147-52

issue

22

eissn

0006-2960

issn

1520-4995

pii

bi980360n

journal_volume

37

pub_type

杂志文章

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