Identification of specific residues of human interleukin 2 that affect binding to the 70-kDa subunit (p70) of the interleukin 2 receptor.
AUTOR(ES)
Collins, L
RESUMO
Analogs of interleukin 2 containing defined amino acid substitutions and deletions were assayed for bioactivity and for competitive binding to the high-affinity human interleukin 2 receptor complex and its two component subunits, a 55-kDa subunit (p55 or TAC) and a 70-kDa subunit (p70). Substitution of Asp20 or deletion of Phe124 resulted in inactive analog proteins that were unable to interact with the high-affinity p55/p70 complex or the intermediate-affinity p70 subunit of the interleukin 2 receptor. These analogs, however, retained the capacity to compete for binding to the low-affinity p55 subunit. The presence of the carboxylic acid in the side chain of Asp20 was necessary for effective binding to the p70 protein. In contrast, substitution of Trp121 and Leu17 created analogs that were inactive in the bioassay and all three binding assays. The effects of these mutations on protein conformation were assessed by circular dichroism. These results demonstrate that specific residues in the NH2 and COOH termini of interleukin 2 are crucial for its structure and activity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=282262Documentos Relacionados
- Suppression of heat-induced hsp70 expression by the 70-kDa subunit of the human Ku autoantigen.
- Interaction of the 82-kDa subunit of the vaccinia virus early transcription factor heterodimer with the promoter core sequence directs downstream DNA binding of the 70-kDa subunit.
- Localization in human interleukin 2 of the binding site to the alpha chain (p55) of the interleukin 2 receptor.
- Detection of three protein binding sites in the serum-regulated promoter of the human gene encoding the 70-kDa heat shock protein.
- Insulin activates a 70-kDa S6 kinase through serine/threonine-specific phosphorylation of the enzyme polypeptide.