Equilibrium denaturation of insulin and proinsulin.


Abstract

The guanidine hydrochloride induced equilibrium denaturation of insulin and proinsulin was studied by using near- and far-ultraviolet (UV) circular dichroism (CD). The denaturation transition of insulin is reversible, cooperative, symmetrical, and the same whether detected by near- or far-UV CD. These results are consistent with a two-state denaturation process without any appreciable equilibrium intermediates. Analysis of the insulin denaturation data yields a Gibbs free energy of unfolding of 4.5 +/- 0.5 kcal/mol. Denaturation of proinsulin detected by near-UV CD appears to be the same as for insulin, but if detected by far-UV CD appears different. The far-UV CD results demonstrate a multiphasic transition with the connecting peptide portion unfolding at lower concentrations of denaturant. Similar studies with the isolated C-peptide show that its conformation and susceptibility to denaturation are independent of the rest of the proinsulin molecule. After the proinsulin denaturation results were adjusted for the connecting peptide contribution, a denaturation transition identical with that of insulin was obtained. These results show that for proinsulin, the connecting peptide segment is not a random coil; it is an autonomous folding unit, and the portion corresponding to insulin is identical with insulin in terms of conformational stability. Study holds ProTherm entries: 3650 Extra Details: additive : EDTA(1 mM), reversible; two-state denaturation;,free energies of unfolding; conformational stability

Submission Details

ID: WZJubuL7

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:22 p.m.

Version: 1

Publication Details
Brems DN;Brown PL;Heckenlaible LA;Frank BH,Biochemistry (1990) Equilibrium denaturation of insulin and proinsulin. PMID:2271596
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
1BZV 1998-11-04T00:00:00+0000 0 [D-ALAB26]-DES(B27-B30)-INSULIN-B26-AMIDE A SUPERPOTENT SINGLE-REPLACEMENT INSULIN ANALOGUE, NMR, MINIMIZED AVERAGE STRUCTURE
1BZV 1998-11-04T00:00:00+0000 0 [D-ALAB26]-DES(B27-B30)-INSULIN-B26-AMIDE A SUPERPOTENT SINGLE-REPLACEMENT INSULIN ANALOGUE, NMR, MINIMIZED AVERAGE STRUCTURE
3WS3 2014-02-28T00:00:00+0000 2.33 Crystal Structure of H-2D in complex with an insulin derived peptide
6CE7 2018-02-11T00:00:00+0000 7.4 Insulin Receptor ectodomain in complex with one insulin molecule
6CE9 2018-02-11T00:00:00+0000 4.3 Insulin Receptor ectodomain in complex with two insulin molecules
6CEB 2018-02-11T00:00:00+0000 4.7 Insulin Receptor ectodomain in complex with two insulin molecules - C1 symmetry
1APH 1992-10-30T00:00:00+0000 2.0 CONFORMATIONAL CHANGES IN CUBIC INSULIN CRYSTALS IN THE PH RANGE 7-11
1APH 1992-10-30T00:00:00+0000 2.0 CONFORMATIONAL CHANGES IN CUBIC INSULIN CRYSTALS IN THE PH RANGE 7-11
1BPH 1992-10-30T00:00:00+0000 2.0 CONFORMATIONAL CHANGES IN CUBIC INSULIN CRYSTALS IN THE PH RANGE 7-11
1BPH 1992-10-30T00:00:00+0000 2.0 CONFORMATIONAL CHANGES IN CUBIC INSULIN CRYSTALS IN THE PH RANGE 7-11

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
547.8 B,D,F,H,J,L Insulin P01338 INS2_BATSP
550.2 B,D,F,H,J,L Insulin P68987 INS_PETMA
550.2 B,D,F,H,J,L Insulin P68988 INS_LAMFL
555.6 B,D,F,H,J,L Insulin C0HJI7 INS1_HUSDA
553.8 B,D,F,H,J,L Insulin C0HJI3 INS2_KATPE
553.8 B,D,F,H,J,L Insulin P09476 INS_ATRSP
553.8 B,D,F,H,J,L Insulin Q9W7R2 INS_VERMO
553.8 B,D,F,H,J,L Insulin P09477 INS_PLAFE
553.8 B,D,F,H,J,L Insulin P04667 INS_ONCKE
555.6 B,D,F,H,J,L Insulin P01340 INS_KATPE
558.6 B,D,F,H,J,L Insulin P83770 INSL_VIGUN
555.6 B,D,F,H,J,L Insulin P12707 INS2_XENLA
577.2 B,D,F,H,J,L Insulin C0HJI8 INS2_HUSDA
579.6 B,D,F,H,J,L Insulin P21563 INS_RODSP
600.0 B,D,F,H,J,L Insulin P81423 INS_ACIGU
557.4 B,D,F,H,J,L Insulin P12706 INS1_XENLA
577.8 B,D,F,H,J,L Insulin P69048 INS_TRASC
577.8 B,D,F,H,J,L Insulin P69047 INS_TRADO
577.8 B,D,F,H,J,L Insulin P67969 INS_STRCA
577.8 B,D,F,H,J,L Insulin P67968 INS_MELGA
577.8 B,D,F,H,J,L Insulin P67970 INS_CHICK
1149.6000000000001 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01323 INS2_RAT
1149.6000000000001 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01326 INS2_MOUSE
578.4 B,D,F,H,J,L Insulin P51463 INS_SELRF
578.4 B,D,F,H,J,L Insulin P68243 INS_CAIMO
578.4 B,D,F,H,J,L Insulin P68245 INS_ANSAN
578.4 B,D,F,H,J,L Insulin P01333 INS_ANAPL
1143.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P18109 INS_DIDVI
559.8 B,D,F,H,J,L Insulin P67971 INS_SAISC
559.8 B,D,F,H,J,L Insulin P67972 INS_AOTTR
1122.6 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01320 INS_CAMDR
1131.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01324 INS_ACOCA
600.0 B,D,F,H,J,L Insulin P01318 INS_SHEEP
1171.2 A,B,C,D,E,F,G,H,I,J,K,L Insulin Q62587 INS_PSAOB
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01315 INS_PIG
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P67974 INS_PHYMC
1171.2 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01310 INS_HORSE
600.0 B,D,F,H,J,L Insulin P06306 INS_FELCA
600.0 B,D,F,H,J,L Insulin P01319 INS_CAPHI
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01321 INS_CANLF
1143.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01317 INS_BOVIN
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P67973 INS_BALPH
1143.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01314 INS_BALBO
1180.2 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01311 INS_RABIT
1180.2 A,B,C,D,E,F,G,H,I,J,K,L Insulin Q91XI3 INS_ICTTR
1151.4000000000003 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01313 INS_CRILO
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin Q8HXV2 INS_PONPY
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P30410 INS_PANTR
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P30406 INS_MACFA
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01308 INS_HUMAN
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin Q6YK33 INS_GORGO
1143.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P01316 INS_ELEMA
1200.0 A,B,C,D,E,F,G,H,I,J,K,L Insulin P30407 INS_CHLAE
600.0 B,D,F,H,J,L Insulin F8WCM5 INSR2_HUMAN
543.0 A,C,E,G,I,K Insulin P01327 INS_CHICH
571.2 A,C,E,G,I,K Insulin P01322 INS1_RAT
571.2 A,C,E,G,I,K Insulin P01325 INS1_MOUSE