Napin from Brassica juncea: Thermodynamic and structural analysis of stability
IR@CFTRI: CSIR-Central Food Technological Research Institute, Mysore
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| Relation |
http://ir.cftri.com/8854/
BBA-02-07 |
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| Title |
Napin from Brassica juncea: Thermodynamic and
structural analysis of stability
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| Creator |
Jyothi, T. C.
Sharmistha, Sinha Sridevi, A. S. |
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| Subject |
04 Mustard seed
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| Description |
The napin from Brassica juncea, oriental mustard, is highly thermostable, proteolysis resistant and allergenic in nature. It consists of two
subunits – one small (29 amino acid residues) and one large (86 amino acids residues) – held together by disulfide bonds. The thermal unfolding
of napin has been followed by differential scanning calorimetry (DSC) and circular dichroism (CD) measurements. The thermal unfolding is
characterized by a three state transition with TM1 and TM2 at 323.5 K and 335.8 K, respectively; ΔCP1 and ΔCP2 are 2.05 kcal mol−1 K−1 and
1.40 kcal mol−1 K−1, respectively. In the temperature range 310–318 K, the molecule undergoes dimerisation. Isothermal equilibrium unfolding
by guanidinium hydrochloride also follows a three state transition, N⇆I⇆U with ΔG1H2O and ΔG2H2O values of 5.2 kcal mol−1 and 5.1 kcal
mol−1 at 300 K, respectively. Excess heat capacity values obtained, are similar to those obtained from DSC measurements. There is an increase in
hydrodynamic radius from 20 Å to 35.0 Å due to unfolding by guanidinium hydrochloride. In silico alignment of sequences of napin has revealed
that the internal repeats (40%) spanning residues 31 to 60 and 73 to 109 are conserved in all Brassica species. The internal repeats may contribute
to the greater stability of napin. A thorough understanding of the structure and stability of these proteins is essential before they can be exploited
for genetic improvements for nutrition.
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| Date |
2007
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Language |
en
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| Identifier |
http://ir.cftri.com/8854/1/Biochimica_et_Biophysica_Acta_%28BBA%29_-_Proteins_%26_Proteomics_1774%287%29_2007_907-919.pdf
Jyothi, T. C. and Sharmistha, Sinha and Sridevi, A. S. (2007) Napin from Brassica juncea: Thermodynamic and structural analysis of stability. Biochimica et Biophysica Acta, 1774. pp. 907-919. |
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