Retracted papers linked to 2007 extortion attempt

Researcher was sent e-mail demanding money.

Two papers retracted in the past few months have been linked to an extortion attempt. Both papers originated from the laboratory of Peter Schultz, a prominent chemist at the Scripps Research Institute in La Jolla, California.

Documents seen recently by Nature show that in 2007, law enforcement officials in San Diego considered a former postdoctoral fellow from the Schultz lab as a possible suspect after another received an anonymous e-mail demanding a $4,000 payment and threatening to reveal alleged fraud.

Peter Schultz. Credit: SCHULTZ LAB

Officials did not pursue the case after the recipient of the e-mail decided not to press charges.

The retracted papers were published in Science1 and the Journal of the American Chemical Society (JACS)2. They claimed to describe the successful incorporation of amino acids linked to sugars at specific positions in proteins made by the bacterium Escherichia coli3. The results were seen as important because proteins with attached sugars, or glycoproteins, are common in nature and are used as drug therapies, but they are hard to produce in the lab using E. coli.

Anonymous e-mail

On 1 March 2007, Zhiwen Zhang, the first author on the Science paper and the third author on the JACS paper, received an e-mail that read in part: "you have fraud on at least 3 papers and you stole library material– I found proof." The author of the e-mail asked Zhang to send cash to a post office box in San Diego, and threatened that if Zhang did not comply, e-mails would be sent to Schultz, Scripps president Richard Lerner, and other scientists and administrators at Scripps and at the University of Texas at Austin, where Zhang began working after he left the Schultz lab in 2004.

The author of the e-mail used the pseudonym "michael pemulis", a reference to the David Foster Wallace novel Infinite Jest. The e-mail said that Schultz "will retract all your post-doctoral work", including the two now-retracted papers, and promised "you lose job".

Zhang says he did not commit fraud. "I did no wrong, no scientific misconduct and no fraud," he says. "I am the victim of an extortion case, and I have suffered dearly."

The e-mail was forwarded to law enforcement officials in San Diego. In March 2007, a southern California multi-agency task force, the Computer and Technology Crime High-Tech Response Team, obtained warrants to search the records of Internet service providers in connection with the case. On 6 April, an officer with the task force notified Zhang that it considered Eric Tippmann, who overlapped with Zhang while both were postdoctoral fellows in Schultz's lab in 2004, to be a suspect. Zhang says that after consulting with Schultz and Lerner, he decided not to press criminal charges. Law enforcement officials have confirmed that the investigation is closed.

Tippmann denies sending the extortion e-mail or contacting Zhang after Zhang left the Schultz lab. "If I was ever briefly mentioned in any investigation, I was never contacted nor interviewed, so this must have been a very short investigation," Tippmann wrote in an e-mail.

In August of this year, Tippmann and his colleagues published a study4 claiming that the experiments reported in the now-retracted papers could not have worked as described. However, Tippmann says he first became concerned about the papers in 2006 after he noticed what he alleges are similarities between mass spectra shown in the retracted JACS paper2 and in an earlier JACS paper5 from the Schultz lab. Tippmann says he also noticed other inconsistencies in some of the lab's papers. For instance, the mass of a myoglobin protein containing a sugar molecule described in the 2004 Science paper1 was reported to be nearly the same as that of a myoglobin lacking a sugar and containing a natural amino acid that was described in the 2004 JACS paper2. Tippmann says he told Schultz and other lab members about these issues, and raised concerns about other work published by the lab. Tippmann, now at Cardiff University in Wales, says he was motivated to raise the concerns after watching other lab members fail to replicate the work.

Zhang calls the issues raised by Tippmann "irrelevant". "It's all false and misleading, and it has all been cleared up," says Zhang, who says that Scripps has looked into the matter and cleared him of fraud and misconduct.


Schultz says that he has reproduced all of the results questioned by Tippmann, including other work that Zhang was involved in, except for the experiments that have now been retracted. He says that he is unsure why the mass spectra in the 2003 and 2004 JACS papers contain some similarities. "My guess is in that case a mistake was made," Schultz says. "That certainly indicates things were done sloppily, which, frankly, is not the case in my other publications."

As for the Science paper, it is possible, Schultz says, that Zhang interpreted a myoglobin without an attached sugar that appeared as a contaminant in the mass spectrum as the glycomyoglobin he intended to make. "Unfortunately without the original notebooks I can't reproduce all the original experiments exactly as they were, and see what was done right and what was done wrong," Schultz says.

"I don't think fraud was committed," says Schultz. He adds that in attempting to reproduce the work reported in the retracted papers, the team "found complexities that were really unusual", such as key experiments that sometimes gave misleading results.

Zhang says that he stands by his original work. He says it is possible that Schultz's lab failed to replicate the retracted papers because it used different conditions or procedures from those he used for the original papers. The lab notebooks describing the original experiments "are no longer available", according to the retraction in Science.

In November 2007, Walter Fast, an associate professor in the same division as Zhang at the University of Texas at Austin, received an anonymous letter, claiming to be from a member of the Schultz lab, alleging that the 2004 Science paper was "fake". Fast says he gave the letter to Zhang and says that Zhang later told him that Scripps had investigated the matter and had not found any wrongdoing. The retractions "came up right when [Zhang] was going for tenure, and it's been hard for him", Fast says.

Lynn Crismon, dean of the school of pharmacy at the University of Texas at Austin, says that tenure decisions are still under review by the university president's executive committee.


  1. 1

    Zhang, Z. et al. Science 303, 371-373 (2004).

  2. 2

    Xu, R. et al. J. Am. Chem. Soc. 126, 15654-15655 (2004).

  3. 3

    Check Hayden, E. Nature 462, 707 (2009).

  4. 4

    Antonczak, A. K., Simova, Z. & Tippmann, E. M. J. Biol. Chem. 284, 28795-28800 (2009).

  5. 5

    Alfonta, L., Zhang, Z., Uryu, S., Loo, J. A. & Schultz, P. G. J. Am. Chem. Soc. 125, 14662-14663 (2003).

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With reporting by Rex Dalton.

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Check Hayden, E. Retracted papers linked to 2007 extortion attempt. Nature (2009).

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