Sequence redesign and the assembly mechanism of the oxytocin/bovine neurophysin I biosynthetic precursor.

Ando S, McPhie P, Chaiken IM

The Journal of biological chemistry1 Sept 1987Cited by 19 (Europe PMC)

PMID3654597DOI10.1016/s0021-9258(18)45151-4PepBankPUB-03654597

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Summary

The structural organization of neurohypophysial hormone biosynthetic precursors and the interdependence between intramolecular folding and precursor self-association were examined using sequence-engineered mutants of the semisynthetic oxytocin/bovine neurophysin precursor (pros-OT/BNPI). In [N alpha 1-Ac,N epsilon 30,71-diacetimidyl, Ala2,des-His106] Pro-Ot/BNPI or [N alpha 1-Ac,Ala2]pros-OT/BNPI), two structural elements (Tyr2 and free alpha-amino group) were eliminated which were predicted to be critical for intramolecular conformation by stabilizing contact between hormone and neurophysin domains. This mutant was used to test the dependence of precursor self-association on intramolecular conformation. In the second mutant precursor, [N alpha 30,71-diacetimidyl,D-Pro7,D-Leu8,des-His106]p ro-OT/BNPI (or [D-Pro7,D-Leu8]pros-OT/BNPI), the stereochemistry at L-Pro7-L-Leu8 was changed to test the extent to which precursor conformation depends on ordered structure in the processing/spacer sequence which connects the interacting hormone and neurophysin I domains. Intramolecular conformation was characterized for the precursor and mutants by analytical affinity chromatography on immobilized hormone analog Met-Tyr-Phe and by circular dichroism. Data obtained by both methods showed that, while pros-OT/BNPI is folded, with hormone domain occupying the hormone-binding site of the neurophysin domain, the alpha-acetyl-Ala2 mutant is not so organized intramolecularly. When pros-OT/BNPI and the alpha-acetyl-Ala2 mutant were eluted on immobilized BNPII to measure self-association propensity, the native-like precursor was found to bind with 12-15-fold higher affinity than the assembly mutant. Thus, while pros-OT/BNPI assumes a molecular structure containing a high-affinity self-association surface induced by intramolecular hormone domain-neurophysin domain interaction, [N alpha 1-Ac,Ala2]pros-OT/BNPI does not. The results with the alpha-acetyl-Ala2 mutant show that intramolecular domain-domain interaction is the obligatory "trigger" which induces the high-affinity precursor self-association that likely drives precursor to aggregated forms in the concentrated intragranular environment that exists in peptide hormone-synthesizing cells. In contrast, affinity chromatographic and circular dichroism properties of the D-Pro7,D-Leu8 mutant show that this intramolecular trigger is dependent, but only weakly, on the conformation of the peptide sequence between domains, as judged by native-like interaction properties below 40 degrees C but lowered stability to elevated temperature.(ABSTRACT TRUNCATED AT 400 WORDS)

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study3

No result from this study comes from a test of the peptide.

Studies that did not test the peptide alone3

In this study, Oxytocin was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking Oxytocin.

01LabNot a test of Oxytocin aloneIn vitro (cell-free)Mechanism
The pros-OT/BNPI precursor is folded, with the hormone domain in the neurophysin binding site, whereas the alpha-acetyl-Ala2 mutant is not organized intramolecularly.
In plain wordsIn lab tests, the oxytocin precursor was folded into a set shape, but the changed version was not.
Peptide
Oxytocin
Outcome
Not applicableIntramolecular folding of precursor and alpha-acetyl-Ala2 mutant
Study
n: not reported in source
Semisynthetic oxytocin/bovine neurophysin precursor and mutants
Outcome group
Receptor activity and mechanism · Pharmacology
Source sentences
Summary
Data obtained by both methods showed that, while pros-OT/BNPI is folded, with hormone domain occupying the hormone-binding site of the neurophysin domain, the alpha-acetyl-Ala2 mutant is not so organized intramolecularly.
1 context sentence(design, population, supporting numbers)
Summary · context
The structural organization of neurohypophysial hormone biosynthetic precursors and the interdependence between intramolecular folding and precursor self-association were examined using sequence-engineered mutants of the semisynthetic oxytocin/bovine neurophysin precursor (pros-OT/BNPI).
In this study, Oxytocin was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Oxytocin.
Show in the study text Report a problemFND-0365459701
02LabNot a test of Oxytocin aloneIn vitro (cell-free)Mechanism
The native-like precursor bound immobilized neurophysin II with 12-15-fold higher affinity than the assembly mutant.
In plain wordsIn lab tests, the oxytocin precursor stuck to a partner protein 12-15-fold more strongly than the changed version.
Peptide
Oxytocin
Outcome
Not applicableSelf-association affinity of precursor versus assembly mutant
Study
n: not reported in source
Semisynthetic oxytocin/bovine neurophysin precursor and mutants
Comparator
Alpha-acetyl-Ala2 assembly mutant
Outcome group
Receptor activity and mechanism · Pharmacology
Measurements
Affinity fold difference
12 to 15 fold
native-like precursor versus assembly mutant
Source sentences
Summary
When pros-OT/BNPI and the alpha-acetyl-Ala2 mutant were eluted on immobilized BNPII to measure self-association propensity, the native-like precursor was found to bind with 12-15-fold higher affinity than the assembly mutant.
1 context sentence(design, population, supporting numbers)
Summary · context
The structural organization of neurohypophysial hormone biosynthetic precursors and the interdependence between intramolecular folding and precursor self-association were examined using sequence-engineered mutants of the semisynthetic oxytocin/bovine neurophysin precursor (pros-OT/BNPI).
In this study, Oxytocin was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Oxytocin.
Show in the study text Report a problemFND-0365459702
03LabNot a test of Oxytocin aloneIn vitro (cell-free)Mechanism
In the D-Pro7,D-Leu8 mutant of the oxytocin/bovine neurophysin precursor, the intramolecular trigger depended only weakly on the conformation of the sequence between the domains, with native-like interaction below 40 degrees C but lower stability at higher temperature.
In plain wordsIn lab tests, a changed version of the oxytocin precursor kept its native-like behavior at lower temperature but was less stable when warmed.
Peptide
Oxytocin
Outcome
Not applicableConformation dependence of the D-Pro7,D-Leu8 mutant precursor
Study
n: not reported in source
Semisynthetic oxytocin/bovine neurophysin precursor and mutants
Outcome group
Receptor activity and mechanism · Pharmacology
Source sentences
Summary
In contrast, affinity chromatographic and circular dichroism properties of the D-Pro7,D-Leu8 mutant show that this intramolecular trigger is dependent, but only weakly, on the conformation of the peptide sequence between domains, as judged by native-like interaction properties below 40 degrees C but lowered stability to elevated temperature
In this study, Oxytocin was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Oxytocin.
Show in the study text Report a problemFND-0365459703

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

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PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Version 2Current
11 Oct 2026, 20:03 UTC
Study results updated
Version 1
9 Oct 2026, 02:54 UTC
First added · source update from Europe PMC

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