Peptide name : Mature Smac (1-4)

Source/Organism : SMAC

Linear/Cyclic : Linear

Chirality : L

Peptide length: 4

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 specified

Other activity : Not found

Amino acid composition bar chart :

Molecular mass : 398.497 Dalton

Aliphatic index : 1.95

Instability index : 55.65

Hydrophobicity (GRAVY) : 2.225

Isoelectric point : 5.57

Charge (pH 7) : -0.2041

Aromaticity : 0

Molar extinction coefficient (cysteine, cystine): (0, 0)

Hydrophobic/hydrophilic ratio : infinite

hydrophobic moment : 1.206

Missing amino acid : W,T,M,E,K,F,D,N,G,C,R,H,Q,S,Y,L

Most occurring amino acid : A

Most occurring amino acid frequency : 1

Least occurring amino acid : A

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.2, 0.2, 0.5)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@@H]1CCCN1C(=O)[C@@H](NC(=O)[C@H](C)N)C(C)C)C(=O)O

1 : Wu G, et al. Structural basis of IAP recognition by Smac/DIABLO. Nature. 2000; 408:1008-12. doi: 10.1038/35050012

Paper title : Structural basis of IAP recognition by Smac/DIABLO.

Doi : https://doi.org/10.1038/35050012

Abstract : Apoptosis is an essential process in the development and homeostasis of all metazoans. The inhibitor-of-apoptosis (IAP) proteins suppress cell death by inhibiting the activity of caspases; this inhibition is performed by the zinc-binding BIR domains of the IAP proteins. The mitochondrial protein Smac/DIABLO promotes apoptosis by eliminating the inhibitory effect of IAPs through physical interactions. Amino-terminal sequences in Smac/DIABLO are required for this function, as mutation of the very first amino acid leads to loss of interaction with IAPs and concomitant loss of Smac/DIABLO function. Here we report the high-resolution crystal structure of Smac/DIABLO complexed with the third BIR domain (BIR3) of XIAP. Our results show that the N-terminal four residues (Ala-Val-Pro-Ile) in Smac/DIABLO recognize a surface groove on BIR3, with the first residue Ala binding a hydrophobic pocket and making five hydrogen bonds to neighbouring residues on BIR3. These observations provide a structural explanation for the roles of the Smac N terminus as well as the conserved N-terminal sequences in the Drosophila proteins Hid/Grim/Reaper. In conjunction with other observations, our results reveal how Smac may relieve IAP inhibition of caspase-9 activity. In addition to explaining a number of biological observations, our structural analysis identifies potential targets for drug screening.