Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
One example: In 1582 the united provinces invited francis, duke of anjou to lead them; but after a failed attempt to take antwerp in 1583, the duke left the netherlands again. after the assassination of william of orange (10 july 1584), both henry iii of france and elizabeth i of england declined the offer of sovereignty. however, the latter agreed to turn the united provinces into a protectorate of england (treaty of nonsuch, 1585), and sent the earl of leicester as governor-general. this was unsuccessful and in 1588 the provinces became a confederacy. the union of utrecht is regarded as the foundation of the republic of the seven united provinces, which was not recognized by the spanish empire until the peace of westphalia in 1648.
Solution is here: In what year did francis, duke of anjou leave the netherlands?
Explanation: The generated question is perfect. Because the question is based on second sentence of the input passage and its answer is 1583.

Now, solve this: Restriction endonucleases play a very important role in genetic engineering and DNA mapping. Among hundreds of restriction endonucleases, the Eco R1 enzyme is the most useful and widely investigated enzyme. After sonication and ultracentrifugation, crude extracts of E. coli RY 13 were purified by employing the polyethyleneimine precipitate, ammonium sulfate precipitate and heparin Sepharose-4B affinity column chromatography. The Eco R1 enzyme were purified at about 42 folds and the specific activity was about 100,000 U/mg of protein. The whole purification procedure was finished within two days. The recovery was about 42%. The enzyme was sufficiently concentrated for direct specific DNA hydrolysis.
Solution:
Which bacteria was EcoRI, restriction endonuclease isolated from?