Serious issues with cryo-EM structures of human prothrombinase

Area of Science:

• Biochemistry
• Structural Biology
• Hematology

Background:

• Thrombin generation from prothrombin involves the prothrombinase enzyme complex (factor Xa and factor Va) on phospholipid membranes.
• Recent studies reported cryogenic electron microscopy (cryo-EM) structures of human prothrombinase.

Purpose of the Study:

• To perform a post hoc analysis of the quality of reported cryo-EM coordinates and maps.
• To assess the validity of claimed intermolecular contacts in the prothrombinase complex structures.

Main Methods:

• Analysis of cryo-EM data coordinates and maps from reported structures (7TPQ and 7TPP).
• Examination of intermolecular contacts described in the original publication.

Main Results:

• The reported cryo-EM structures are deeply flawed.
• Not a single claimed intermolecular contact is supported by the provided maps.
• The structures lack useful information on prothrombinase complex assembly and function.

Conclusions:

• The two reported structures of human prothrombinase do not provide valid insights.
• The claimed breakthrough regarding prothrombinase assembly and function is unsubstantiated.