Biggest Molecule—Titanic Titin

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Science  22 Dec 1995:
Vol. 270, Issue 5244, pp. 1905c
DOI: 10.1126/science.270.5244.1905c

In 1995 biologists smashed records by cloning the DNA for the largest protein molecule known. The aptly named titin weighs in at a molecular weight of 3 million and consists of a continuous chain of 27,000 amino acids, making it 20 to 50 times larger than the average-size protein.

Like the Titans of Greek mythology, titin is known not only for its size but for its strength. Each molecule spans a distance of 1 micrometer and acts as a microscopic spring that pulls a muscle fiber back into shape after it is stretched.

Illustration by Terry E. Smith

Further Reading:

  1. Links:Sequence information for titin is available at Science's Beyond the Printed Page.

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