Rationale for Bcl-xL/Bad peptide complex formation from structure, mutagenesis, and biophysical studies.
The three-dimensional structure of the anti-apoptotic protein Bcl-xL complexed to a 25-residue peptide from the death promoting region of Bad was determined using NMR spectroscopy. Although the overall structure is similar to Bcl-xL bound to a 16-residue peptide from the Bak protein (Sattler et al., 1997), the Bad peptide forms additional interactions with Bcl-xL. However, based upon site-directed mutagenesis experiments, these additional contacts do not account for the increased affinity of the Bad 25-mer for Bcl-xL compared to the Bad 16-mer. Rather, the increased helix propensity of the Bad 25-mer is primarily responsible for its greater affinity for Bcl-xL. Based on this observation, a pair of 16-residue peptides were designed and synthesized that were predicted to have a high helix propensity while maintaining the interactions important for complexation with Bcl-xL. Both peptides showed an increase in helix propensity compared to the wild-type and exhibited an enhanced affinity for Bcl-xL.
Petros
A M
AM
Pharmaceutical Discovery Division, Abbott Laboratories, Abbott Park, Illinois 60064-6098, USA.
Nettesheim
D G
DG
Wang
Y
Y
Olejniczak
E T
ET
Meadows
R P
RP
Mack
J
J
Swift
K
K
Matayoshi
E D
ED
Zhang
H
H
Thompson
C B
CB
Fesik
S W
SW
D000595:Amino Acid Sequence; D017209:Apoptosis; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism; D011485:Protein Binding; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein
C494819:BAD protein, human; C494811:BCL2L1 protein, human; D002352:Carrier Proteins; D010455:Peptides; D019253:Proto-Oncogene Proteins c-bcl-2; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein