Residue 75 of interleukin-8 is crucial for its interactions with glycosaminoglycans.
The interactions between regulatory proteins such as interleukin-8 (IL-8) and glycosaminoglycans are of great interest both for the general understanding of regulatory processes in biology and for the development of implant coatings and innovative materials that suppress undesired immune responses and improve wound healing. In previous work, a number of residues of IL-8 that interact strongly with several glycosaminoglycans (GAGs) have been identified. In particular, the negatively charged Glu75 was reported to be involved in interactions with charged GAGs. To improve understanding of the role of this residue, we generated a selectively (15)N-labeled E75K variant of IL-8(1-77) by expressed protein ligation. NMR and fluorescence spectroscopy in combination with molecular modeling were applied to evaluate the particular role of residue 75 in interactions with GAGs. Remarkably, more residues in the variant responded to GAG binding than in the wild-type. For the first time, we identified amino acids 34 to 36 as additional residues in the loop region of IL-8(1-77) that participate in the interactions with GAGs. These findings indicate that the N terminus of the E75K variant is more important as a second binding site for GAGs than that of the wild-type IL-8(1-77).
Institute of Biochemistry, Universität Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany.
Karoline
K
Nordsieck
Annelie
A
Pichert
Sergey A
SA
Samsonov
Lars
L
Thomas
Christian
C
Berger
M Teresa
MT
Pisabarro
Daniel
D
Huster
Annette G
AG
Beck-Sickinger
D006025:Glycosaminoglycans / Q000378:metabolism*; D006801:Humans; D016209:Interleukin-8 / Q000737:chemistry* / Q000378:metabolism*; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D009154:Mutation; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D013379:Substrate Specificity
D006025:Glycosaminoglycans; D016209:Interleukin-8; D010446:Peptide Fragments