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Conformational transmission in proinsulin and its derivatives: a study using H/D exchange

Conformational transmission in proinsulin and its derivatives: a study using H/D exchange
Conformational transmission in proinsulin and its derivatives: a study using H/D exchange
Buffalo proinsulin cDNA was isolated, sequenced and shown to differ from that of its bovine counterpart in six nucleotides. However, at the protein level the predicted sequences of the two species are identical. Buffalo M-proinsulin, containing the initiation methionine, was produced in Escherichia coli and purified to give Mr of 8812. Following the replacement of 99% of the exchangeable hydrogen atoms with deuterons a preparation containing 131 D atoms was obtained. Buffer exchange of the latter into a protio medium led to, the immediate release of 109 (±1) D atoms into the medium and the retention of 22 (±1) D atoms in the protein. The slow exchange of these D atoms was studied at 0 °C/pH 2.8. Insulin derived from buffalo proinsulin as well as bovine when deuteriated and buffer exchanged, similarly, gave the retention of 25 (±1) D atoms. The data show that the secondary structure of the insulin core present within buffalo/bovine proinsulin contains 5 (±1) fewer slow exchanging hydrogen atoms than are present in the final hormone. This effect is attributed, predominantly, to the long range influence of the C-peptide, composed of 26 residues, on the insulin core of buffalo proinsulin. In contrast, in the case of human proinsulin, comprising 31 amino acids in the C-peptide, the secondary structure of the insulin core within human proinsulin is closer to that of insulin itself.
buffalo/bovine proinsulin, expression, refolding and mass spectrometry, proinsulin and insulin replacement of exchangeable hydrogen atoms with deuterons, proinsulin–insulin structure comparison, long range and proximal effects in buffalo proinsulin and derivatives
1387-3806
36-43
Younas, Hooria
cd0f1b06-520b-46a6-b729-d829d178d3f2
Gardner, Qurra-tul-Ann Afza
6b69c9b8-b0c3-45ee-b7b8-43fcdaff9567
Rashid, Naeem
81704b5b-8999-4883-8e58-0c09ab9b63e1
Wright, J. Neville
e53ee4b9-10f5-4365-a9f2-5a7b0eacd86d
Akhtar, Muhammad
a4174002-a6bd-4678-8e63-4cbe607a672d
Younas, Hooria
cd0f1b06-520b-46a6-b729-d829d178d3f2
Gardner, Qurra-tul-Ann Afza
6b69c9b8-b0c3-45ee-b7b8-43fcdaff9567
Rashid, Naeem
81704b5b-8999-4883-8e58-0c09ab9b63e1
Wright, J. Neville
e53ee4b9-10f5-4365-a9f2-5a7b0eacd86d
Akhtar, Muhammad
a4174002-a6bd-4678-8e63-4cbe607a672d

Younas, Hooria, Gardner, Qurra-tul-Ann Afza, Rashid, Naeem, Wright, J. Neville and Akhtar, Muhammad (2011) Conformational transmission in proinsulin and its derivatives: a study using H/D exchange. International Journal of Mass Spectrometry, 302 (1-3), 36-43. (doi:10.1016/j.ijms.2010.07.020).

Record type: Article

Abstract

Buffalo proinsulin cDNA was isolated, sequenced and shown to differ from that of its bovine counterpart in six nucleotides. However, at the protein level the predicted sequences of the two species are identical. Buffalo M-proinsulin, containing the initiation methionine, was produced in Escherichia coli and purified to give Mr of 8812. Following the replacement of 99% of the exchangeable hydrogen atoms with deuterons a preparation containing 131 D atoms was obtained. Buffer exchange of the latter into a protio medium led to, the immediate release of 109 (±1) D atoms into the medium and the retention of 22 (±1) D atoms in the protein. The slow exchange of these D atoms was studied at 0 °C/pH 2.8. Insulin derived from buffalo proinsulin as well as bovine when deuteriated and buffer exchanged, similarly, gave the retention of 25 (±1) D atoms. The data show that the secondary structure of the insulin core present within buffalo/bovine proinsulin contains 5 (±1) fewer slow exchanging hydrogen atoms than are present in the final hormone. This effect is attributed, predominantly, to the long range influence of the C-peptide, composed of 26 residues, on the insulin core of buffalo proinsulin. In contrast, in the case of human proinsulin, comprising 31 amino acids in the C-peptide, the secondary structure of the insulin core within human proinsulin is closer to that of insulin itself.

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Published date: April 2011
Keywords: buffalo/bovine proinsulin, expression, refolding and mass spectrometry, proinsulin and insulin replacement of exchangeable hydrogen atoms with deuterons, proinsulin–insulin structure comparison, long range and proximal effects in buffalo proinsulin and derivatives
Organisations: Centre for Biological Sciences

Identifiers

Local EPrints ID: 335610
URI: http://eprints.soton.ac.uk/id/eprint/335610
ISSN: 1387-3806
PURE UUID: ea0828d2-2d19-4b75-a9c4-0fe5b8cdb1f5

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Date deposited: 13 Mar 2012 12:37
Last modified: 19 Jul 2019 22:05

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