Experimental Data Snapshot
(1998) Nature 391: 608-612
Many serine proteases are targets for therapeutic intervention because they often play key roles in disease. Small molecule inhibitors of serine proteases with high affinity are especially interesting as they could be used as scaffolds from which to develop drugs selective for protease targets. One such inhibitor is bis(5-amidino-2-benzimidazolyl)methane (BABIM), standing out as the best inhibitor of trypsin (by a factor of over 100) in a series of over 60 relatively closely related analogues. By probing the structural basis of inhibition, we discovered, using crystallographic methods, a new mode of high-affinity binding in which a Zn2+ ion is tetrahedrally coordinated between two chelating nitrogens of BABIM and two active site residues, His57 and Ser 195. Zn2+, at subphysiological levels, enhances inhibition by over 10(3)-fold. The distinct Zn2+ coordination geometry implies a strong dependence of affinity on substituents. This unique structural paradigm has enabled development of potent, highly selective, Zn2+-dependent inhibitors of several therapeutically important serine proteases, using a physiologically ubiquitous metal ion.
 Explore in 3D: Structure |Sequence Annotations |Electron Density |Validation Report |Ligand Interaction (BAH)
Biological assembly 1 assigned by authors.
Macromolecule Content 
Entity ID: 1 | |||||
|---|---|---|---|---|---|
| Molecule | Chains | Sequence Length | Organism | Details | Image |
| Thrombin light chain | A [auth L] | 36 | Homo sapiens | Mutation(s): 0  EC: 3.4.21.5 | ![]() |
UniProt & NIH Common Fund Data Resources | |||||
Find proteins for P00734 (Homo sapiens) Explore P00734  Go to UniProtKB:  P00734 | |||||
PHAROS:  P00734 GTEx:  ENSG00000180210  | |||||
Entity Groups  | |||||
| Sequence Clusters | 30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity | ||||
| UniProt Group | P00734 | ||||
Sequence AnnotationsExpand | |||||
| |||||
Entity ID: 2 | |||||
|---|---|---|---|---|---|
| Molecule | Chains | Sequence Length | Organism | Details | Image |
| Thrombin heavy chain | B [auth H] | 259 | Homo sapiens | Mutation(s): 0  EC: 3.4.21.5 | ![]() |
UniProt & NIH Common Fund Data Resources | |||||
Find proteins for P00734 (Homo sapiens) Explore P00734  Go to UniProtKB:  P00734 | |||||
PHAROS:  P00734 GTEx:  ENSG00000180210  | |||||
Entity Groups  | |||||
| Sequence Clusters | 30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity | ||||
| UniProt Group | P00734 | ||||
Sequence AnnotationsExpand | |||||
| |||||
Find similar proteins by: Sequence | 3D Structure
Entity ID: 3 | |||||
|---|---|---|---|---|---|
| Molecule | Chains | Sequence Length | Organism | Details | Image |
| Hirudin-2 | C [auth I] | 11 | Hirudo medicinalis | Mutation(s): 0  | ![]() |
UniProt | |||||
Find proteins for P28504 (Hirudo medicinalis) Explore P28504  Go to UniProtKB:  P28504 | |||||
Entity Groups  | |||||
| Sequence Clusters | 30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity | ||||
| UniProt Group | P28504 | ||||
Sequence AnnotationsExpand | |||||
| |||||
| Ligands 3 Unique | |||||
|---|---|---|---|---|---|
| ID | Chains | Name / Formula / InChI Key | 2D Diagram | 3D Interactions | |
| BAH Query on BAH Download Ideal Coordinates CCD File  | H | BIS(5-AMIDINO-2-BENZIMIDAZOLYL)METHANE KETONE HYDRATE C17 H18 N8 O2 ZLAHDRAQCSQPOC-UHFFFAOYSA-P | |||
| ZN Query on ZN Download Ideal Coordinates CCD File  | D [auth L], E [auth H], F [auth H] | ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N | |||
| NA Query on NA Download Ideal Coordinates CCD File  | G [auth H] | SODIUM ION Na FKNQFGJONOIPTF-UHFFFAOYSA-N | |||
| Modified Residues 1 Unique | |||||
|---|---|---|---|---|---|
| ID | Chains | Type | Formula | 2D Diagram | Parent |
| TYS Query on TYS | C [auth I] | L-PEPTIDE LINKING | C9 H11 N O6 S | TYR | |
| Length ( Å ) | Angle ( ˚ ) |
|---|---|
| a = 71.22 | α = 90 |
| b = 71.88 | β = 100.69 |
| c = 72.65 | γ = 90 |
| Software Name | Purpose |
|---|---|
| bioteX | data collection |
| bioteX | data reduction |
| X-PLOR | model building |
| Quanta | model building |
| Insight II | model building |
| X-PLOR | refinement |
| bioteX | data scaling |
| X-PLOR | phasing |
RCSB PDB Core Operations are funded by theU.S. National Science Foundation (DBI-2321666), theUS Department of Energy (DE-SC0019749), and theNational Cancer Institute,National Institute of Allergy and Infectious Diseases, andNational Institute of General Medical Sciences of theNational Institutes of Health under grant R01GM157729.