The common C‐terminal sequences of substance P and neurokinin A contact the same region of the NK‐1 receptor

FEBS Letters

Leeman, Susan E.¹  Boyd, Norman D.¹  Bremer, Andrew A.¹ 

[1] Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, L-611, 80 E. Concord Street, Boston, MA 02118, USA

关键词: Substance P;    Neurokinin A;    NK-1 receptor;    Photoaffinity labeling;    Bpa;    p-benzoyl-L-phenylalanine;    BH;    Bolton Hunter (N-succinimidyl-3[4-hydroxyphenyl]propionate);    CHO;    Chinese hamster ovary;    DTT;    D;    L-dithiothreitol;    E2;    NK-1R second extracellular loop;    125I-Bpa7NKA;    125I-iodohistidyl1-Bpa7NKA;    125I-BH-Bpa8SP;    125I-Bolton-Hunter3-Bpa8SP;    MALDI;    matrix-assisted laser desorption ionization;    NKA;    neurokinin A;    NK-1R;    NK-1 receptor;    rNK-1R;    rat NK-1 receptor;    SDS–PAGE;    sodium dodecyl sulfate–polyacrylamide gel electrophoresis;    SP;    substance P;   

DOI  :  10.1016/S0014-5793(00)02228-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Although neurokinin A (NKA), a tachykinin peptide with sequence homology to substance P (SP), is a weak competitor of radiolabeled SP binding to the NK-1 receptor (NK-1R), more recent direct binding studies using radiolabeled NKA have demonstrated an unexpected high-affinity interaction with this receptor. To document the site of interaction between NKA and the NK-1R, we have used a photoreactive analogue of NKA containing p-benzoyl-L-phenylalanine (Bpa) substituted in position 7 of the peptide. Peptide mapping studies of the receptor photolabeled by ¹²⁵I-iodohistidyl¹-Bpa⁷NKA have established that the site of photoinsertion is located within a segment of the receptor extending from residues 178 to 190 (VVCMIEWPEHPNR). We have previously shown that ¹²⁵I-BH-Bpa⁸SP, a photoreactive analogue of SP, covalently attaches to M¹⁸¹ within this same receptor sequence. Importantly, both of these peptides (¹²⁵I-iodohistidyl¹-Bpa⁷NKA and ¹²⁵I-BH-Bpa⁸SP) have the photoreactive amino acid in an equivalent position within the conserved tachykinin carboxyl-terminal tail. In this report, we also show that site-directed mutagenesis of M¹⁸¹ to A¹⁸¹ in the NK-1R results in a complete loss of photolabeling of both peptides to this receptor site, indicating that the equivalent position of SP and NKA, when bound to the NK-1R, contact the same residue.

【 授权许可】

Unknown