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Structural determination of the active site of a sweet protein A 1 H NMR investigation of pMNEI
Author(s) -
Tancredi T.,
Iijima H.,
Saviano G.,
Amodeo P.,
Temussi P.A.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81138-c
Subject(s) - side chain , aspartame , residue (chemistry) , chemistry , stereochemistry , loop (graph theory) , crystallography , biochemistry , mathematics , polymer , organic chemistry , combinatorics
pMNEI, a single chain sweet protein related to monellin, has been studied by means of 1 H NMR at 500 MHz. A partial sequential assignment performed by means of the MCD method allowed the determination of the secondary structure of a large portion of the β‐sheet of pMNEI that contains a likely ‘sweet finger’: the loop connecting the β‐strands from residue 59 to residue 78, corresponding to segment 16–35 of the A chain of monellin. The detailed three‐dimensional structure of the loop (Tyr 66 ‐Ala 67 ‐Ser 68 ‐Asp 69 ), determined from several interresidue and intraresidue NOEs and subsequent energy minimization, shows that the side chains or Tyr 66 and Asp 69 fit our model of the sweet receptor in a manner very similar to that of the side chains of Phe and Asp or aspartame.