Open AccessStructural analysis of ASCUT‐1, a protein component of the cuticle of the parasitic nematode Ascaris lumbricoides
Author(s) -
D'Auria Sabato,
Rossi Mosè,
Tanfani Fabio,
Bertoli Enrico,
Parise Giuliano,
Bazzicalupo Paolo
Publication year - 1998
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1998.2550588.x
Subject(s) - ascaris lumbricoides , nematode , cuticle (hair) , chemistry , protein tertiary structure , infrared spectroscopy , protein secondary structure , circular dichroism , crystallography , biophysics , biochemistry , biology , organic chemistry , anatomy , helminths , immunology , ecology
CUT‐1 from the intestinal parasitic nematode Ascaris lumbricoides is a protein component of the insoluble residue of the cuticle, cuticlin. It contains the CUT‐1‐like domain which is shared by members of a novel family of components of extracellular matrices. The structure and the thermal stability of recombinant CUT‐1 from A. lumbricoides (ASCUT‐1) were investigated by Fourier‐transform infrared (FT‐IR) and CD spectroscopy. The data revealed that the secondary structure of the protein at 20 +C, both as insoluble inclusion bodies or in soluble form, contains about 50 %β structure, 14 %α‐helix and 25 % turns. A tendency of A. lumbricoides CUT‐1 to form aggregates was documented by FT‐IR spectroscopy which showed also that the addition of SDS disrupts these interactions. Near‐ultraviolet CD spectra confirmed these data and suggested that phenylalanine residues are probably involved in intermolecular hydrophobic interactions responsible for the tendency of the protein to aggregate. Near‐ultraviolet spectra showed also that part of the cysteine residues forms disulphide bridges responsible for the tertiary architecture of the protein. Finally, FT‐IR and CD data revealed that ASCUT‐1 is very stable at high temperatures. This stability and the tendency of ASCUT‐1 to form aggregates suggest that these properties may be important for a protein which is a component of a particularly resistant extracellular matrix such as the nematode cuticle.