The Different Folding Behavior of Insulin and Insulin-like Growth Factor 1 Is Mainly Controlled by Their B-Chain/Domain

Guo, Zhan‐Yun; Shen, Lu; Yang, Feng

doi:10.1021/bi011166v

Cited by 32 publications

(50 citation statements)

References 53 publications

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“…It is the different disulfide pairing that results in the different retention time of peak B of isomer 1 and peak C of isomer 2. Together with the result of CD analysis, the folding behavior of IGF-1/mini-IGF-1 (37), and the results of ILP and its mutants (40,41), it can reasonably be presumed that the disulfides of isomer 2 are identical to those of insulin/ native IGF-1, while the disulfides of isomer 1 are identical to those of swap IGF-1. Moreover, all of the three major fragments of [pE]ILP have the expected molecular masses; therefore, the different molecular masses between ILP and [pE]ILP must be caused by the difference of the three N-terminal residues, Gln-Ala-Glu.…”

Section: Peptide Mapping Of the Disulfide Isomers Of Ilp And [Pe]-ilpmentioning

confidence: 82%

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Refolding of Amphioxus Insulin-like Peptide: Implications of a Bifurcating Evolution of the Different Folding Behavior of Insulin and Insulin-like Growth Factor 1

et al. 2003

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Insulin and insulin-like growth factor 1 (IGF-1) share high sequence homology, but their folding behaviors are significantly different: insulin folds into one unique thermodynamically controlled structure, while IGF-1 folds into two thermodynamically controlled disulfide isomers. However, the origin of their different folding behaviors is still elusive. The amphioxus insulin-like peptide (ILP) is thought to be the common ancestor of insulin and IGF-1. A recombinant single-chain ILP has been expressed previously, and now its folding behavior is investigated. The folding behavior of ILP shows the characteristics of both insulin and IGF-1. On one hand, two thermodynamically controlled disulfide isomers of ILP have been identified; on the other hand, the content of isomer 1 (its disulfides are deduced identical to those of swap IGF-1) is much less than that of isomer 2 (its disulfides are deduced identical to those of native IGF-1); that is, more than 96% of ILP folds into the native structure. The present results suggest that the different folding behaviors of insulin and IGF-1 are acquired through a bifurcating evolution: the tendency of forming the thermodynamically controlled non-native disulfide isomer is diminished during evolution from ILP to insulin, while this tendency is amplified during evolution from ILP to IGF-1. Moreover, the N-terminal Gln residue of ILP can spontaneously form a pyroglutamate residue, and its cyclization has a significant effect on the folding behavior of ILP: the percentage of isomer 1 is approximately 2-fold that of isomer 1 of the noncyclized ILP; that is, isomer 1 becomes more favored when the N-terminal residue of ILP is cyclized. So, we deduce that the N-terminal residues have a significant effect on the folding properties of insulin, IGF-1, and ILP.In the 1960s Anfinsen and co-workers first demonstrated the three-dimensional structure of a globular protein is uniquely determined by its amino acid sequence (1). Since then, significant advances have been made in the understanding of protein folding through experimental and theoretical approaches. For small proteins with two-state folding, topology is a major determinant of the folding rate and greatly influences the structure of the transition-state ensemble (2-4). Studies on the disulfide-coupled folding of some small globular proteins, such as BPTI, 1 RNase A, and EGF, have revealed a sequence of preferred kinetic intermediates which define a folding pathway (5-12). In vivo the protein folding is assisted by the molecular chaperones, especially for large proteins (13-15); some chaperones even can provide the missing steric information for protein folding (16).Insulin is an extensively studied small globular protein with A-and B-chains linked by three disulfides (one intrachain bond, A6-A11; two interchain bonds, A7-B7 and A20-B19). Its three-dimensional structure has been well solved by X-ray crystallography (17,(18)(19)(20)(21) since the 1970s. Although the separate A-and B-chains of insulin can be recombined success...

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Section: Peptide Mapping Of the Disulfide Isomers Of Ilp And [Pe]-ilpmentioning

confidence: 82%

“…The different folding behavior of insulin/PIP and IGF-1 is mainly controlled by their B-chain/domain that controls the different energetic state of the intra-A-chain/domain disulfide (37,38).…”

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confidence: 99%

Refolding of Amphioxus Insulin-like Peptide: Implications of a Bifurcating Evolution of the Different Folding Behavior of Insulin and Insulin-like Growth Factor 1

et al. 2003

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“…Our previous results demonstrated that the different folding behavior of insulin and IGF-1 is mainly controlled by their B-chain/domains (24,26) (28). They proposed that the N-terminal extension imparts a steric constraint at a crucial point in folding, thus allowing native disulfide bonds to form efficiently.…”

Section: Discussionmentioning

confidence: 99%

“…Mini-IGF-1 (the C-terminus of IGF-1 B-domain and the N-terminus of IGF-1 A-domain were linked together by a dipeptide, Ala-Lys, and B30Thr was also replaced by Lys) has bifurcating folding behavior similar to that of IGF-1 (24). Previously, on the basis of studies of folding behavior of mini-IGF-1, PIP, and hybrids Ins(A)/IGF-1(B) and Ins(B)/ IGF-1(A), we have demonstrated that the different folding behavior of insulin/PIP and IGF-1/mini-IGF-1 is mainly controlled by their B-chain/domains (24). The different energetic states of the intra-A-chain/domain disulfide (14,25), which had been suggested to correspond to the different folding behavior of insulin and IGF-1, are also controlled by their B-chain/domains (26).…”

mentioning

confidence: 99%

“…So we use mini-IGF-1 (24) and PIP (22) as peptide models to test this hypothesis. We prepared the following four peptide models by means of protein engineering (22,24) IGF-1/ IGF-1 folded into two thermodynamically structures, is encoded/written in its sequence 1-9, while sequence 1-10 of B-chain in insulin/PIP plays an important role in the guide of its unique disulfide pairing during the folding process.…”

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Sequences of B-Chain/Domain 1−10/1−9 of Insulin and Insulin-like Growth Factor 1 Determine Their Different Folding Behavior

et al. 2004

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Although insulin and insulin-like growth factor-1 (IGF-1) belong to one family, insulin folds into one thermodynamically stable structure, while IGF-1-folds into two thermodynamically stable structures (native and swap forms). We have demonstrated previously that the bifurcating folding behavior of IGF-1 is mainly controlled by its B-domain. To further elucidate which parts of the sequences determine their different folding behavior, by exchanging the N-terminal sequences of mini-IGF-1 and recombinant porcine insulin precursor (PIP), we prepared four peptide models: [1-9]PIP, [1-10]mini-IGF-1, [1-4]PIP, and [1-5]mini-IGF-1 by means of protein engineering, and their disulfide rearrangement, V8 digestion, circular dichroic spectra, disulfide stability, and in vitro refolding were investigated. Among them only [1-9]-PIP, like mini-IGF-1/IGF-1, was expressed in yeast as two isomers: isomer 1 (corresponding to swap IGF-1) and isomer 2 (corresponding to native IGF-1), which are supported by the experimental results of disulfide rearrangements, peptide mapping of V8 endoprotenase digests, circular dichroic analysis, in vitro refolding, and disulfide stability analysis. The other peptide models, [1-10]mini-IGF-1, [1-4]PIP, and [1-5]mini-IGF-1, fold into one stable structure as PIP does, which indicates that sequence 1-4 of mini-IGF-1 is important for the folding behavior of mini-IGF-1/IGF-1 but not sufficient to lead to a bifurcating folding. The results demonstrated that the folding information, by which mini-IGF-1/IGF-1-folds into two thermodynamically structures, is encoded/written in its sequence 1-9, while sequences 1-10 of B chain in insulin/PIP play an important role in the guide of its unique disulfide pairing during the folding process.Insulin is a structurally and functionally well-characterized small globular protein with A-and B-chains linked by three disulfides. Its three-dimensional structure has been well defined by X-ray crystallography (1) and NMR (2-4) since the 1970s. Insulin-like growth factor-1 (IGF-1) 1 is a 70-residue single-chain globular protein composed of B-, C-, A-, and D-domains from the N-terminus to the C-terminus (5). Its B-and A-domains are homologous to the B-and A-chains of insulin, respectively; its 12-residue C-domain is analogous to the C-peptide of proinsulin, but they share no homology; its C-terminal 8-residue D-domain has no counterpart in insulin. The three-dimensional structure of IGF-1 has also been well-defined by X-ray crystallography (6, 7) and NMR (8, 9). Insulin and IGF-1 belong to the same superfamily. They have a common structural motif (10, 11) and share homologous sequence, similar three-dimensional structure (1,6,7), and a common ancestor (12,13). Both mainly consist of three R-helical segments (A2-A8, A13-A19, and B9-B19 in insulin; 8-18, 42-49, and 54-61 in IGF-1) in the A-and B-chains/domains; the three R-helical segments are stabilized by three identical disulfides (A6-A11, A7-B7, and A20-B19 in insulin; 47-52, 6-48, and 18-61 in IGF-1); and when IGF-1...

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In Vitro Folding of Single/Double Chain Insulins and Related Proteins

Yang

2011

Folding of Disulfide Proteins

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The Different Folding Behavior of Insulin and Insulin-like Growth Factor 1 Is Mainly Controlled by Their B-Chain/Domain

Cited by 32 publications

References 53 publications

Refolding of Amphioxus Insulin-like Peptide: Implications of a Bifurcating Evolution of the Different Folding Behavior of Insulin and Insulin-like Growth Factor 1

Refolding of Amphioxus Insulin-like Peptide: Implications of a Bifurcating Evolution of the Different Folding Behavior of Insulin and Insulin-like Growth Factor 1

Sequences of B-Chain/Domain 1−10/1−9 of Insulin and Insulin-like Growth Factor 1 Determine Their Different Folding Behavior

In Vitro Folding of Single/Double Chain Insulins and Related Proteins

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