... way very similar topY429pY431 with the residues Y) 2, Y+ 3, Y+ 4 and Y+ 5building up hydrophobic contacts to the SOCS-3 SH2domain. Serine at position Y+ 1 forms a hydrogen bond with the backbone ... phosphorylatedpeptide pY429pY431 (pYpY). In comparison, the muta-tion only marginally reduces the interaction with the single phosphorylated peptides pY429F431 (pYF) andF429pY431 (FpY) suggesting ... In the model structure, phenyl-alanine at position Y) 2 of the peptide contacts G53.Threonine Y+ 1 can undergo a hydrophobic contact with bC of K91 as well as a hydrogen bond with the backboneNH-group...