2z3p
From Proteopedia
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| , resolution 2.50Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Gene: | Aat (Escherichia coli) | ||||||
| Activity: | Leucyltransferase, with EC number 2.3.2.6 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
complex structure of LF-transferase and leucine
Overview
Eubacterial leucyl/phenylalanyl-tRNA protein transferase (LF-transferase) catalyses peptide-bond formation by using Leu-tRNA(Leu) (or Phe-tRNA(Phe)) and an amino-terminal Arg (or Lys) of a protein, as donor and acceptor substrates, respectively. However, the catalytic mechanism of peptide-bond formation by LF-transferase remained obscure. Here we determine the structures of complexes of LF-transferase and phenylalanyl adenosine, with and without a short peptide bearing an N-terminal Arg. Combining the two separate structures into one structure as well as mutation studies reveal the mechanism for peptide-bond formation by LF-transferase. The electron relay from Asp 186 to Gln 188 helps Gln 188 to attract a proton from the alpha-amino group of the N-terminal Arg of the acceptor peptide. This generates the attacking nucleophile for the carbonyl carbon of the aminoacyl bond of the aminoacyl-tRNA, thus facilitating peptide-bond formation. The protein-based mechanism for peptide-bond formation by LF-transferase is similar to the reverse reaction of the acylation step observed in the peptide hydrolysis reaction by serine proteases.
About this Structure
2Z3P is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Protein-based peptide-bond formation by aminoacyl-tRNA protein transferase., Watanabe K, Toh Y, Suto K, Shimizu Y, Oka N, Wada T, Tomita K, Nature. 2007 Oct 18;449(7164):867-71. Epub 2007 Sep 23. PMID:17891155
Page seeded by OCA on Thu Mar 20 18:51:48 2008
