1FA3

SOLUTION STRUCTURE OF MNEI, A SWEET PROTEIN

1FA3 の概要

• エントリーDOI: 10.2210/pdb1fa3/pdb
• NMR情報: BMRB: 4638
• 分子名称: MNEI SWEET PROTEIN RELATED TO MONELLIN (1 entity in total)
• 機能のキーワード: 5 stranded beta sheet 1 helix, structural protein
• 由来する生物種: Dioscoreophyllum cumminsii (serendipity berry)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 11287.85

構造登録者

Temussi, P.A.,Spadaccini, R. (登録日: 2000-07-12, 公開日: 2000-11-16, 最終更新日: 2024-05-22)

主引用文献

Spadaccini, R.,Crescenzi, O.,Tancredi, T.,De Casamassimi, N.,Saviano, G.,Scognamiglio, R.,Di Donato, A.,Temussi, P.A.
Solution structure of a sweet protein: NMR study of MNEI, a single chain monellin.
J.Mol.Biol., 305:505-514, 2001

PubMed Abstract: The sweet protein MNEI is a construct of 96 amino acid residues engineered by linking, with a Gly-Phe dipeptide, chains B and A of monellin, a sweet protein isolated from Discoreophyllum cuminsii. Here, the solution structure of MNEI was determined on the basis of 1169 nuclear Overhauser enhancement derived distance restraints and 184 dihedral angle restraints obtained from direct measurement of three-bond spin coupling constants. The identification of hydrogen bonded NH groups was obtained by a combination of H/(2)H exchange data and NH resonance temperature coefficients derived from a series of HSQC spectra in the temperature range 278-328 K. The good resolution of the structure is reflected by the Z-score of the quality checking program in WHAT IF (-0.61). The topology of MNEI, like that of natural monellin and of SCM, another single-chain monellin, is typical of the cystatin superfamily: an alpha-helix cradled into the concave side of a five-strand anti-parallel beta-sheet. The high resolution (14 restraints/residue) 3D structure of MNEI shows close similarity to the crystal structures of natural monellin and of SCM but differs from the solution structure of SCM. The structures of SCM in the crystal and in solution differ in some of the secondary structure elements, but most of all in the relative arrangement of the elements: the four main beta-strands that surround the helix in the crystal structure of SCM, are displaced far from the helix in the solution structure of SCM. These differences were attributed to the fact that SCM is a monomer in solution and a dimer in the crystal. This result is at variance with the observation that our solution structure, like that of SCM, corresponds to a monomeric state of the protein, as demonstrated by the insensitivity of HSQC spectra to extreme dilution (down to 20 microM). On the basis of the solution structure of MNEI it is possible to propose that the main glucophores are hosted on loop L34, whereas the N-terminal and C-terminal regions host two other important interaction regions, centered around segments 6-9 and 94-96.

PubMed: 11152608
DOI: 10.1006/jmbi.2000.4304

実験手法

SOLUTION NMR