Structural basis for the persistence of homing endonucleases in transcription factor IIB inteins

Author:

Iwaï, Hideo

Mikula, Kornelia M

Oeemig, Jesper S

Zhou, Dongwen

Li, Mi

Wlodawer, Alexander
Author Address

Research Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki. P.O. Box 65, Helsinki, FIN, -00014, Finland. Electronic address: hideo.iwai@helsinki.fi., Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA., Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA; Basic Science Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA., Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA. Electronic address: wlodawer@nih.gov.,

Abstract:

Inteins are mobile genetic elements that are spliced out of proteins after translation. Some inteins contain a homing endonuclease (HEN) responsible for their propagation. Hedgehog/INTein (HINT) domains catalyzing protein splicing and their nested HEN domains are thought to be functionally independent because of the existence of functional mini-inteins without HEN domains. Despite the lack of obvious mutualism between HEN and HINT domains, HEN domains are persistently found at one specific site in inteins, indicating their potential functional role in protein splicing. Here we report crystal structures of inactive and active mini-inteins derived from inteins residing in the transcription factor IIB of Methanococcus jannaschii and Methanocaldococcus vulcanius, revealing a novel modified HINT fold that might provide new insights on the mutualism between the HEN and HINT domains. We propose an evolutionary model of inteins and a functional role of HEN domains in inteins. Copyright © 2017. Published by Elsevier Ltd.

See More

Author Address