Application of fragment screening and fragment linking to the discovery of novel thrombin inhibitors.
The screening of fragments is an alternative approach to high-throughput screening for the identification of leads for therapeutic targets. Fragment hits have been discovered using X-ray crystallographic screening of protein crystals of the serine protease enzyme thrombin. The fragment library was designed to avoid any well-precedented, strongly basic functionality. Screening hits included a novel ligand (3), which binds exclusively to the S2-S4 pocket, in addition to smaller fragments which bind to the S1 pocket. The structure of these protein-ligand complexes are presented. A chemistry strategy to link two such fragments together and to synthesize larger drug-sized compounds resulted in the efficient identification of hybrid inhibitors with nanomolar potency (e.g., 7, IC50 = 3.7 nM). These potent ligands occupy the same area of the active site as previously described peptidic inhibitors, while having very different chemical architecture.
Howard
Nigel
N
Astex Therapeutics, 436 Cambridge Science Park, Milton Road, Cambridge CB4 0QA, United Kingdom.
Abell
Chris
C
Blakemore
Wendy
W
Chessari
Gianni
G
Congreve
Miles
M
Howard
Steven
S
Jhoti
Harren
H
Murray
Christopher W
CW
Seavers
Lisa C A
LC
van Montfort
Rob L M
RL
D002219:Carbamates / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D016208:Databases, Factual; D006801:Humans; D008958:Models, Molecular; D011487:Protein Conformation; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013449:Sulfonamides / Q000138:chemical synthesis / Q000737:chemistry; D013777:Tetrazoles / Q000138:chemical synthesis / Q000737:chemistry; D013917:Thrombin / Q000037:antagonists & inhibitors* / Q000737:chemistry*
D002219:Carbamates; D013449:Sulfonamides; D013777:Tetrazoles; D013917:Thrombin