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Study · Not a test of the peptide alone · 2007

4 results

Substituted NDP-MSH peptides paired with mutant melanocortin-4 receptors demonstrate the role of transmembrane 6 in receptor activation.

Fleck BA, Ling N, Chen C

Biochemistry23 Aug 2007Cited by 12 (Europe PMC)

PMID17713970 (opens in a new tab)DOI10.1021/bi700406k (opens in a new tab)PepBankPUB-17713970
Publisher pagePubMedAsk about this study
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Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: Publisher copyright. Results still quote short attributed sentences.

Results from this study4

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

Studies that did not test the peptide alone4

In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).

  1. 01LabNot a test of Melanotan I (afamelanotide) aloneIn vitro (cells)Mechanism

    Alanine substitution of d-Phe7, Arg8 or Trp9 in NDP-MSH peptides reduced binding energy but did not remove receptor activation.

    In plain wordsIn lab tests, changing these three amino acids in the peptide weakened binding but did not stop MC4 receptor activation.

    Peptide
    Melanotan I (afamelanotide)
    Outcome
    No significant changeReceptor activation by Ala-substituted d-Phe7, Arg8 and Trp9 peptides
    Study

    humann: not reported in source

    Outcome group
    Receptor activity and mechanism · Pharmacology

    Source sentences

    Summary
    Alanine substitution indicated that the d-Phe7, Arg8, and Trp9 side chains contribute binding energy but are not essential for the receptor activation event.
    1 context sentence
    Summary · context
    The aim of this study was to investigate the molecular mechanism of human MC4R activation by [Nle4, d-Phe7]alpha-melanocyte-stimulating hormone (NDP-MSH)

    In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).

  2. 02LabNot a test of Melanotan I (afamelanotide) aloneIn vitro (cells)Mechanism

    The His6 to Ala6 substitution in NDP-MSH reduced MC4 receptor activation but did not affect affinity.

    In plain wordsIn lab tests, changing His6 to alanine lowered MC4 receptor activation but not binding.

    Peptide
    Melanotan I (afamelanotide)
    Outcome
    DecreaseReceptor activation by His6 to Ala6 peptide
    Study

    humann: not reported in source

    Outcome group
    Receptor activity and mechanism · Pharmacology

    Source sentences

    Summary
    Conversely, His6 to Ala6 substitution reduced receptor activation but did not affect affinity.
    1 context sentence
    Summary · context
    The aim of this study was to investigate the molecular mechanism of human MC4R activation by [Nle4, d-Phe7]alpha-melanocyte-stimulating hormone (NDP-MSH)

    In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).

  3. 03LabNot a test of Melanotan I (afamelanotide) aloneIn vitro (cells)Mechanism

    Chlorine substitutions on the d-Phe7 side chain of NDP-MSH inhibited MC4 receptor activation.

    In plain wordsIn lab tests, adding chlorine to the d-Phe7 part of the peptide blocked MC4 receptor activation.

    Peptide
    Melanotan I (afamelanotide)
    Outcome
    DecreaseReceptor activation by chlorine-substituted d-Phe7 peptides
    Study

    humann: not reported in source

    Outcome group
    Receptor activity and mechanism · Pharmacology

    Source sentences

    Summary
    Chlorine substitutions on the d-Phe7 side chain also inhibited receptor activation.
    1 context sentence
    Summary · context
    The aim of this study was to investigate the molecular mechanism of human MC4R activation by [Nle4, d-Phe7]alpha-melanocyte-stimulating hormone (NDP-MSH)

    In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).

  4. 04LabNot a test of Melanotan I (afamelanotide) aloneIn vitro (cells)Mechanism

    F261(6.51)A and F284(7.35)A receptor mutations restored efficacy to His6 and d-Phe7 substituted NDP-MSH peptides that had lost efficacy at the wild-type receptor.

    In plain wordsIn lab tests, two receptor mutations brought back the activity of the changed peptides.

    Peptide
    Melanotan I (afamelanotide)
    Outcome
    IncreaseEfficacy of His6 and d-Phe7 substituted peptides at F261A and F284A mutant receptors
    Study

    humann: not reported in source

    Comparator
    Wild-type receptor
    Outcome group
    Receptor activity and mechanism · Pharmacology

    Source sentences

    Summary
    F261(6.51)A and F284(7.35)A receptor mutations acted as gain-of-function mutations, restoring efficacy to the His6 and d-Phe7 substituted peptides that had lost efficacy at the wild-type receptor.
    1 context sentence
    Summary · context
    The aim of this study was to investigate the molecular mechanism of human MC4R activation by [Nle4, d-Phe7]alpha-melanocyte-stimulating hormone (NDP-MSH)

    In this study, Melanotan I (afamelanotide) 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 Melanotan I (afamelanotide).

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

Version history

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

  1. Version 2Current

    13 Oct 2026, 21:44 UTC

    Study results updated

  2. Version 1

    13 Oct 2026, 16:31 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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