Report

A bacterial global regulator forms a prion

See allHide authors and affiliations

Science  13 Jan 2017:
Vol. 355, Issue 6321, pp. 198-201
DOI: 10.1126/science.aai7776

eLetters is an online forum for ongoing peer review. Submission of eLetters are open to all. eLetters are not edited, proofread, or indexed.  Please read our Terms of Service before submitting your own eLetter.

Compose eLetter

Plain text

  • Plain text
    No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Author Information
First or given name, e.g. 'Peter'.
Your last, or family, name, e.g. 'MacMoody'.
Your email address, e.g. higgs-boson@gmail.com
Your role and/or occupation, e.g. 'Orthopedic Surgeon'.
Your organization or institution (if applicable), e.g. 'Royal Free Hospital'.
Statement of Competing Interests
CAPTCHA

This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Image CAPTCHA
Enter the characters shown in the image.

Vertical Tabs

  • Analogues of non-essential amino acids in the treatment of diseases
    • Qiuyun Liu, Professor, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
    • Other Contributors:
      • Meng Xing, Student, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
      • Junxie Huang, Student, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
      • Hongyu Zhong, student, Sheffield Medical School, University of Sheffield, Sheffield S10 2RX, United Kingdom

    Numerous proteins pertinent to human diseases have overrepresented amino acids such as glycine, proline, hydroxyproline, glutamine, etc. (1-3) These amino acids possess secondary chemical bonding to protons and/or non-proton cations, enhancing the formation of acids or/and the generation of insoluble and rigid salts with organic acids, etc. (4-5) As building blocks of proteins, they are non-essential, therefore a carbohydrate diet does not work for relevant patients. Compounds with similar structures to the aforementioned amino acids might be clinically beneficial as they can compete with each other in cellular metabolism. Clinical trials must be conducted to confirm the efficacy and safety of the chemicals. Drug development pipelines need to aim at such amino acids in addition to protein drug targets.

    Meng Xing, 1,3 Junxie Huang, 1,3 Hongyu Zhong, 2,3 Qiuyun Liu 1*
    1 Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals, Biomedical Center, State Key Laboratory of Biocontrol, Lab of Microbial Metabolic Engineering and Synthetic Biology, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
    2 Department of Infection, Immunity & Cardiovascular Disease, Sheffield Medical School, University of Sheffield, Beech Hill Rd, Sheffield S10 2RX, United Kingdom
    3 Equal contributions.

    *Correspondence author.
    E-mail address: lsslqy@mail.sysu.ed...

    Show More
    Competing Interests: None declared.
  • Prion proteins and secondary chemical bonding
    • Qiuyun Liu, Professor, Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals, Sun Yat-sen University
    • Other Contributors:
      • Shixiang Gao, Student, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
      • Kaiping Cheng, Student, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
      • Yunfan Shi, Student, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
      • Feng Wang, Professor, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Australia

    The glycine contents in the prion proteins of Bos Taurus and Homo sapiens are near or about 20% (GenBank accession number ABJ52648.1, ABW89582.1 and AAA60182.1). The overrepresented glycine residues in these proteins suggest that high content of particulate amino acids may be implicated in the etiology of the illness. The σ22 element for the deprotonated carboxyl group in glycine corroborated the presence of moderate strength hydrogen bonds with the carbonyl oxygen (1-2). However the longer bond length of carbonyl carbon with carbonyl oxygen in glycine than that of valine means that carbonyl oxygen in glycine may be strong in secondary chemical bonding with non-proton cations (3). This is corroborated by the increased solubility of glycine in the presence of either NaCl or KCl (4). Numerous other amino acids such as tryptophan and proline also contribute to secondary chemical bonding in proteins. In addition to the increased proton traffic, proton antiport and osmotic stress, secondary chemical bonding with some non-proton cations enhances the formation of insoluble and rigid salts of organic acids and so on, which may trigger cell death (4-6). Compounds with similar structures to oxalate such as ethanol and acetic acid could extend lifespans (7-8), perhaps by the inhibition of oxalate generation. The hydrogen bond strengths based on the σ22 element of the 13C chemical shift anisotropy for the deprotonated carboxyl groups of numerous amino acids are reported in the referen...

    Show More
    Competing Interests: None declared.
  • Prions, bacteria, and eukaryotes
    • Giovanni Di Guardo, Associate Professor, University of Teramo, Faculty of Veterinary Medicine, Località Piano d'Accio, 64100 - Teramo, Italy

    The identification of a prion-like domain, functionally similar to that of a yeast prion-forming protein, in the transcription terminator Rho of Clostridium botulinum (Cb-Rho), along with the amyloidogenicity conferred by it on Cb-Rho, represent extraordinarily relevant findings (1). Noteworthy, a recent study has shown that lactic acid, a common bacterial metabolite, is a powerful inducer in yeast cells of [GAR+], a prion-like genetic element allowing the simultaneous metabolism of glucose and other carbon sources (2). Still of interest, the amyloid-ß peptide, a protein crucially involved in Alzheimer’s disease pathogenesis, has been reported to bind and trap bacterial pathogens inside the brain, thereby behaving like a natural antibiotic (3).
    Although no doubt seems to exist that, based upon the results of this elegant Science work (1), Cb-Rho acts as a prion-like element of inheritance in bacteria, I do not entirely agree with the Authors’ conclusion, “suggesting that the emergence of prions predates the evolutionary split between eukaryotes and bacteria”. As a matter of fact, although this would appear to be absolutely plausible from the biological standpoint, prior evidence of similar or related prion-like domains in Rho or Rho-like proteins from other Clostridium genus members should be obtained to justify the Authors’ statement. In this respect, Clostridium (C.) baratii, C. butyricum, and C. tetani, which are phylogenetically related to C. botulinum (4), coul...

    Show More
    Competing Interests: None declared.