Combination of Trp and Glu residues for recognition of mRNA cap structure. Analysis of m7G base recognition site of human cap binding protein (IF-4E) by site-directed mutagenesis.
Four mutants of the human cap binding protein (hCBP), in which Trp-102, Glu-103, Asp-104 or Glu-105 was changed to the aliphatic Leu or Ala, were prepared, and their cap binding abilities were examined. Cap binding abilities of two mutants, W102L (Trp-102----Leu) and E105A (Glu-105----Ala), were significantly decreased in comparison with the wild-type hCBP. This result suggests that Trp-102 and Glu-105 are both necessary for the cap binding, and the most probable binding mode with the m7G of cap structure is the combination of the stacking by Trp-102 and the hydrogen-bond pairing by Glu-105, as was already proposed from the model studies.
Ueda
H
H
Osaka University of Pharmaceutical Sciences, Japan.
Iyo
H
H
Doi
M
M
Inoue
M
M
Ishida
T
T
Morioka
H
H
Tanaka
T
T
Nishikawa
S
S
Uesugi
S
S
D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics*; D005971:Glutamates / Q000235:genetics*; D018698:Glutamic Acid; D006151:Guanosine / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010448:Peptide Initiation Factors / Q000235:genetics*; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps / Q000737:chemistry / Q000378:metabolism*; D014364:Tryptophan / Q000235:genetics*
D002352:Carrier Proteins; D005971:Glutamates; D010448:Peptide Initiation Factors; D039381:RNA Cap-Binding Proteins; D012315:RNA Caps; D006151:Guanosine; C016578:7-methylguanosine; D018698:Glutamic Acid; D014364:Tryptophan