Display Settings:


Send to:

Choose Destination
See comment in PubMed Commons below
Nucleic Acids Res. 2009 Aug;37(14):4787-98. doi: 10.1093/nar/gkp506. Epub 2009 Jun 10.

Functional importance of crenarchaea-specific extra-loop revealed by an X-ray structure of a heterotetrameric crenarchaeal splicing endonuclease.

Author information

  • 1Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. yoshinas@m.u-tokyo.ac.jp


Archaeal splicing endonucleases (EndAs) are currently classified into three groups. Two groups require a single subunit protein to form a homodimer or homotetramer. The third group requires two nonidentical protein components for the activity. To elucidate the molecular architecture of the two-subunit EndA system, we studied a crenarchaeal splicing endonuclease from Pyrobaculum aerophilum. In the present study, we solved a crystal structure of the enzyme at 1.7-A resolution. The enzyme adopts a heterotetrameric form composed of two catalytic and two structural subunits. By connecting the structural and the catalytic subunits of the heterotetrameric EndA, we could convert the enzyme to a homodimer that maintains the broad substrate specificity that is one of the characteristics of heterotetrameric EndA. Meanwhile, a deletion of six amino acids in a Crenarchaea-specific loop abolished the endonuclease activity even on a substrate with canonical BHB motif. These results indicate that the subunit architecture is not a major factor responsible for the difference of substrate specificity between single- and two-subunit EndA systems. Rather, the structural basis for the broad substrate specificity is built into the crenarchaeal splicing endonuclease itself.

[PubMed - indexed for MEDLINE]
Free PMC Article

Images from this publication.See all images (5)Free text

Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk