PDBsum entry 1u0n

Blood clotting

PDB id: 1u0n

Contents

Protein chains

208 a.a. *

133 a.a. *

125 a.a. *

265 a.a. *

* Residue conservation analysis

PDB id:

1u0n

Name:

Blood clotting

Title:

The ternary von willebrand factor a1-glycoprotein ibalpha-botrocetin complex

Structure:

Von willebrand factor. Chain: a. Fragment: vwfa 1. Engineered: yes. Botrocetin. Chain: b. Fragment: alpha chain. Synonym: platelet coagglutinin. Botrocetin.

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: vwf,f8vwf. Expressed in: escherichia coli. Expression_system_taxid: 562. Bothrops jararaca. Jararaca. Organism_taxid: 8724.

Biol. unit:

Dimer (from PQS)

Resolution:

2.95Å R-factor: 0.213 R-free: 0.276

Authors:

K.Fukuda,R.C.Liddington

Key ref:

K.Fukuda et al. (2005). The snake venom protein botrocetin acts as a biological brace to promote dysfunctional platelet aggregation. Nat Struct Mol Biol, 12, 152-159. PubMed id: 15665869 DOI: 10.1038/nsmb892

Date:

13-Jul-04 Release date: 19-Apr-05

Protein chain

P04275  (VWF_HUMAN) -  von Willebrand factor from Homo sapiens

Seq: 2813 a.a.

Struc: 208 a.a.*

Protein chain

P22029  (SLEA_BOTJA) -  Snaclec botrocetin subunit alpha from Bothrops jararaca

Seq: 133 a.a.

Struc: 133 a.a.

Protein chain

P22030  (SLEB_BOTJA) -  Snaclec botrocetin subunit beta from Bothrops jararaca

Seq: 125 a.a.

Struc: 125 a.a.

Protein chain

P07359  (GP1BA_HUMAN) -  Platelet glycoprotein Ib alpha chain from Homo sapiens

Seq: 652 a.a.

Struc: 265 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

DOI no: 10.1038/nsmb892

Nat Struct Mol Biol 12:152-159 (2005)

PubMed id: 15665869

The snake venom protein botrocetin acts as a biological brace to promote dysfunctional platelet aggregation.

K.Fukuda, T.Doggett, I.J.Laurenzi, R.C.Liddington, T.G.Diacovo.

ABSTRACT

Botrocetin is a snake venom protein that enhances the affinity of the A1 domain of plasma von Willebrand factor (vWF) for the platelet receptor glycoprotein Ibalpha (GPIbalpha), an event that contributes to bleeding and host death. Here we describe a kinetic and crystallographic analysis of this interaction that reveals a novel mechanism of affinity enhancement. Using high-temporal-resolution microscopy, we show that botrocetin decreases the GPIbalpha off-rate two-fold in both human and mouse complexes without affecting the on-rate. The key to this behavior is that, upon binding of GPIbalpha to vWF-A1, botrocetin prebound to vWF-A1 makes no contacts initially with GPIbalpha, but subsequently slides around the A1 surface to form a new interface. This two-step mechanism and flexible coupling may prevent adverse alterations in on-rate of GPIbalpha for vWF-A1, and permit adaptation to structural differences in GPIbalpha and vWF in several prey species.

Selected figure(s)

Figure 5.
Figure 5. The effect of botrocetin on the kinetics of the GPIb -vWF-A1 tether bond. (a,b) Botrocetin does not enhance the cellular on-rate for either the human or mouse GPIb -vWF-A1 tether bond as observed for the type 2B mutation I546V. An enhancement in cellular on-rate is denoted as an increase in tethering frequency of protein-coated beads. Data represent mean s.d. for three independent experiments. WT, wild type.

Figure 7.
Figure 7. Proposed schematic model for the two-step mechanism of interaction between the botrocetin -vWF-A1 binary complex and GPIb .

The above figures are reprinted by permission from Macmillan Publishers Ltd: Nat Struct Mol Biol (2005, 12, 152-159) copyright 2005.

Figures were selected by an automated process.