Peptide name : LIB178

Source/Organism : BH3-only, Direct activators, BIM analogues

Linear/Cyclic : Linear

Chirality : L

Peptide length: 26

C-terminal modification: Linear

N-terminal modification : Not found

Non-natural peptide information: None

Assay type : Not specified

Assay time : Not found

Activity : Not found

Cell line : Not found

Cancer type : Not found

Other activity : Not found

Amino acid composition bar chart :

Molecular mass : 3128.435 Dalton

Aliphatic index : 0.603

Instability index : 70.2346

Hydrophobicity (GRAVY) : -0.811

Isoelectric point : 4.9358

Charge (pH 7) : -1.491

Aromaticity : 0.153

Molar extinction coefficient (cysteine, cystine): (8480, 8480)

Hydrophobic/hydrophilic ratio : 1

hydrophobic moment : 0.6595

Missing amino acid : C,H,T,K,S,L

Most occurring amino acid : A

Most occurring amino acid frequency : 5

Least occurring amino acid : M

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.3, 0.1, 0.2)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@H](CCC(=O)O)NC(=O)[C@@H]1CCCN1C(=O)[C@H](CCCNC(=N)N)NC(=O)[C@@H](N)CCSC)C(=O)N[C@@H](Cc1c[nH]c2ccccc12)C(=O)N[C@@H](C)C(=O)N[C@@H](C)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@@H](CCC(=O)O)C(=O)N[C@H](C(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](C)C(=O)NCC(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](CCC(=O)O)C(=O)N[C@@H](Cc1ccccc1)C(=O)N[C@@H](CC(N)=O)C(=O)N[C@@H](C)C(=O)N[C@@H](Cc1ccc(O)cc1)C(=O)N[C@@H](Cc1ccc(O)cc1)C(=O)N[C@@H](C)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@H](C(=O)O)C(C)C)[C@@H](C)CC

1 : Dutta S, et al. Determinants of BH3 binding specificity for Mcl-1 versus Bcl-xL. J Mol Biol. 2010; 398:747-62. doi: 10.1016/j.jmb.2010.03.058

Paper title : Determinants of BH3 binding specificity for Mcl-1 versus Bcl-xL.

Doi : https://doi.org/10.1016/j.jmb.2010.03.058

Abstract : Interactions among Bcl-2 family proteins are important for regulating apoptosis. Prosurvival members of the family interact with proapoptotic BH3 (Bcl-2-homology-3)-only members, inhibiting execution of cell death through the mitochondrial pathway. Structurally, this interaction is mediated by binding of the alpha-helical BH3 region of the proapoptotic proteins to a conserved hydrophobic groove on the prosurvival proteins. Native BH3-only proteins exhibit selectivity in binding prosurvival members, as do small molecules that block these interactions. Understanding the sequence and structural basis of interaction specificity in this family is important, as it may allow the prediction of new Bcl-2 family associations and/or the design of new classes of selective inhibitors to serve as reagents or therapeutics. In this work, we used two complementary techniques--yeast surface display screening from combinatorial peptide libraries and SPOT peptide array analysis--to elucidate specificity determinants for binding to Bcl-x(L)versus Mcl-1, two prominent prosurvival proteins. We screened a randomized library and identified BH3 peptides that bound to either Mcl-1 or Bcl-x(L) selectively or to both with high affinity. The peptides competed with native ligands for binding into the conserved hydrophobic groove, as illustrated in detail by a crystal structure of a specific peptide bound to Mcl-1. Mcl-1-selective peptides from the screen were highly specific for binding Mcl-1 in preference to Bcl-x(L), Bcl-2, Bcl-w, and Bfl-1, whereas Bcl-x(L)-selective peptides showed some cross-interaction with related proteins Bcl-2 and Bcl-w. Mutational analyses using SPOT arrays revealed the effects of 170 point mutations made in the background of a peptide derived from the BH3 region of Bim, and a simple predictive model constructed using these data explained much of the specificity observed in our Mcl-1 versus Bcl-x(L) binders.