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1 H NMR evidence that Glu‐38 interacts with the N‐terminal functional domain in interleukin‐8
Author(s) -
Rajarathnam Krishnakumar,
Clark-Lewis Ian,
Dewald Beatrice,
Baggiolini Marco,
Sykes Brian D.
Publication year - 1996
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/s0014-5793(96)01277-x
Subject(s) - chemistry , amide , side chain , nuclear magnetic resonance spectroscopy , two dimensional nuclear magnetic resonance spectroscopy , carboxylate , stereochemistry , proton nmr , proton , chemical shift , protein structure , crystallography , biochemistry , organic chemistry , polymer , physics , quantum mechanics
In order to assess the importance of the buried Glu‐38 observed in the structure of interleukin‐8, an analog in which Glu‐38 was replaced with Ala (E38A analog) was investigated by 1 H NMR spectroscopy and neutrophil activation. Detailed analysis of the NMR NOESY data showed that the solution structure of the E38A analog is essentially the same as that for the native protein. Also, the neutrophil elastase activity of the E38A analog was similar to that of the native protein. However, the Gln‐8 and Cys‐9 amide proton chemical shifts, which are significantly downfield‐shifted in the native protein, exhibit more ‘normal’ values. This observation indicates that in the native protein, Glu‐38 side‐chain carboxylate interacts with Gln‐8 and Cys‐9 amide protons. Although the N‐terminal residues are critical for function, this interaction is not essential for neutrophil activation.