Evidence for a second type of fibril branch point in fibrin polymer
networks, the trimolecular junction
MW Mosesson, JP DiOrio, KR Siebenlist, JS Wall and JF Hainfeld
Sinai Samaritan Medical Center, University of Wisconsin Medical School,
Milwaukee 53233.
Fibrin molecules polymerize to double-stranded fibrils by intermolecular
end-to-middle domain pairing of complementary polymerization sites,
accompanied by fibril branching to form a clot network. Mass/length
measurements on scanning transmission electron microscopic images of
fibrils comprising branch points showed two types of junctions.
Tetramolecular junctions occur when two fibrils converge, creating a third
branch with twice the mass/length of its constituents. Newly recognized
trimolecular junctions have three fibril branches of equal mass/length, and
occur when an extraneous fibrin molecule initiates branching in a
propagating fibril by bridging across two unpaired complementary
polymerization sites. When trimolecular junctions predominate, clots
exhibit nearly perfect elasticity.
Volume 82,
Issue 5,
pp. 1517-1521,
09/01/1993
Copyright © 1993 by The American Society of Hematology
