Abstract
The widely used molecular evolutionary clock assumes the divergent evolution of proteins. Convergent evolution has been proposed only for small protein elements but not for an entire protein fold. We investigated the structural basis of the protein splicing mechanism by class 3 inteins, which is distinct from class 1 and 2 inteins. We gathered structural and mechanistic evidence supporting the notion that the Hedgehog/INTein (HINT) superfamily fold, commonly found in protein splicing and related phenomena, could be an example of convergent evolution of an entire protein fold. We propose that the HINT fold is a structural and biochemical solution for trans-peptidyl and trans-esterification reactions.
Abbreviations
- CBD
- chitin-binding domain
- BI
- branched intermediate
- BIL
- Bacterial Intein-Like
- HINT
- Hedgehog/INTein
- Hh-C
- the C-terminal domain of the Hedgehog protein or hog protein
- IMAC
- immobilized metal affinity chromatography
- IPTG
- isopropyl-β-D-thiogalactoside
- MchDnaB1 intein
- DnaB1 intein from Mycobacterium chimaera
- PDB
- Protein Data Bank
- r.m.s.d.
- root-mean-square deviation
- PEG
- polyethylene glycol
- PMSF
- phenylmethane sulfonyl fluoride
- DTT
- dithiothreitol
Copyright
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