Computer-aided molecular modeling and activity estimation for ligand screening with specific phage clone as the target / 南方医科大学学报

To investigate the interaction between tumor necrosis factor alpha (TNF alpha) mimotopes and TNF alpha-binding peptides screened from random phage display peptide library with TNF alpha mimotopes displayed on phage clone as the target, the computational docking program AutoDock (with confirmation calculations using Discover) was used to predict and analyze the binding modes of LLT-18 (TNF alpha binding peptide, sequence EHMALTYPFRPP) with TNF alpha, after which LCS-7 (TNF alpha mimic phage clone, displayed positive sequence c-RRPAQSG-c) was docked to LLT-18 manually. The binding between LLT-18 and TNF alpha or LCS-7 was stabilized predominantly through electrostatic interaction and H-bond formation. The Arg residues in TNF alpha or LCS-7 were important for their interaction with LLT-18. For LLT-18, the key amino acid residues were Glu1, His2, Met3 and Tyr7. These results suggest the feasibility of screening ligand to single epitope with specific phage clone as the target, and of predicting the interaction between small peptides by computer-aided molecular modeling.

Screening of short peptides binding to cell surface interleukin-2 receptor alpha chain / 南方医科大学学报

<p><b>OBJECTIVE</b>To screen and characterize the short peptides which bind specifically to interleukin-2 (IL-2) receptor alpha chain (IL-2Ralpha) for acquisition of small antagonists for blocking the binding of IL-2 with IL-2Ralpha.</p><p><b>METHODS</b>12-mer phage displayed peptide library was screened with the target cells of MT-2 cells which expressed IL-2Ralpha at high levels. The binding phage clones were eluted by anti-IL-2Ralpha monoclonal antibody. After 3 rounds of screening, the positive phage clones were identified by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, and the amino acid sequences of the positive clones were deduced from the DNA sequences.</p><p><b>RESULTS</b>Seven positive clones were screened out of the 17 phage clones bound to MT-2 cells. The positive clone M15 could bind specifically to MT-2 cell and PHA-activated peripheral blood monouclear cells. Amino acid sequence analysis identified 6 sequences, all of which contained hydrophilic residues, and 5 of these 6 sequences included Tyr, Phe and Leu conservative residues.</p><p><b>CONCLUSION</b>The peptide sequences containing Tyr, Phe conservative residues identified in this study can bind to cell surface IL-2Ralpha.</p>