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
ID: WZJubuL7
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:22 p.m.
Version: 1
Colors: | D | E | R | H | K | S | T | N | Q | A | V | I | L | M | F | Y | W | C | G | P |
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Percent Identity | Matching Chains | Protein | Accession | Entry Name |
---|---|---|---|---|
1200.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P67973 | INS_BALPH |
1200.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01321 | INS_CANLF |
1200.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P30407 | INS_CHLAE |
1200.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | Q6YK33 | INS_GORGO |
1200.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01308 | INS_HUMAN |
1180.2 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | Q91XI3 | INS_ICTTR |
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 | P30410 | INS_PANTR |
1200.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P67974 | INS_PHYMC |
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 | Q8HXV2 | INS_PONPY |
1180.2 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01311 | INS_RABIT |
571.2 | A,C,E,G,I,K | Insulin | P01325 | INS1_MOUSE |
571.2 | A,C,E,G,I,K | Insulin | P01322 | INS1_RAT |
1149.6000000000001 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01326 | INS2_MOUSE |
1149.6000000000001 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01323 | INS2_RAT |
1131.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01324 | INS_ACOCA |
1151.4000000000003 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01313 | INS_CRILO |
1171.2 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01310 | INS_HORSE |
1171.2 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | Q62587 | INS_PSAOB |
1143.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01316 | INS_ELEMA |
1143.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01317 | INS_BOVIN |
1122.6 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01320 | INS_CAMDR |
543.0 | A,C,E,G,I,K | Insulin | P01327 | INS_CHICH |
1143.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P01314 | INS_BALBO |
1143.0 | A,B,C,D,E,F,G,H,I,J,K,L | Insulin | P18109 | INS_DIDVI |
600.0 | B,D,F,H,J,L | Insulin | F8WCM5 | INSR2_HUMAN |
600.0 | B,D,F,H,J,L | Insulin | P01319 | INS_CAPHI |
600.0 | B,D,F,H,J,L | Insulin | P06306 | INS_FELCA |
600.0 | B,D,F,H,J,L | Insulin | P01318 | INS_SHEEP |
559.8 | B,D,F,H,J,L | Insulin | P67972 | INS_AOTTR |
559.8 | B,D,F,H,J,L | Insulin | P67971 | INS_SAISC |
578.4 | B,D,F,H,J,L | Insulin | P01333 | INS_ANAPL |
578.4 | B,D,F,H,J,L | Insulin | P68245 | INS_ANSAN |
578.4 | B,D,F,H,J,L | Insulin | P68243 | INS_CAIMO |
578.4 | B,D,F,H,J,L | Insulin | P51463 | INS_SELRF |
577.8 | B,D,F,H,J,L | Insulin | P67970 | INS_CHICK |
577.8 | B,D,F,H,J,L | Insulin | P67968 | INS_MELGA |
577.8 | B,D,F,H,J,L | Insulin | P67969 | INS_STRCA |
577.8 | B,D,F,H,J,L | Insulin | P69047 | INS_TRADO |
577.8 | B,D,F,H,J,L | Insulin | P69048 | INS_TRASC |
557.4 | B,D,F,H,J,L | Insulin | P12706 | INS1_XENLA |
600.0 | B,D,F,H,J,L | Insulin | P81423 | INS_ACIGU |
579.6 | B,D,F,H,J,L | Insulin | P21563 | INS_RODSP |
577.2 | B,D,F,H,J,L | Insulin | C0HJI8 | INS2_HUSDA |
555.6 | B,D,F,H,J,L | Insulin | P12707 | INS2_XENLA |
558.6 | B,D,F,H,J,L | Insulin | P83770 | INSL_VIGUN |
555.6 | B,D,F,H,J,L | Insulin | P01340 | INS_KATPE |
553.8 | B,D,F,H,J,L | Insulin | P04667 | INS_ONCKE |
553.8 | B,D,F,H,J,L | Insulin | P09477 | INS_PLAFE |
553.8 | B,D,F,H,J,L | Insulin | Q9W7R2 | INS_VERMO |
553.8 | B,D,F,H,J,L | Insulin | P09476 | INS_ATRSP |
553.8 | B,D,F,H,J,L | Insulin | C0HJI3 | INS2_KATPE |
555.6 | B,D,F,H,J,L | Insulin | C0HJI7 | INS1_HUSDA |
550.2 | B,D,F,H,J,L | Insulin | P68988 | INS_LAMFL |
550.2 | B,D,F,H,J,L | Insulin | P68987 | INS_PETMA |
547.8 | B,D,F,H,J,L | Insulin | P01338 | INS2_BATSP |