The mechanism for activation of GTP hydrolysis on the ribosome.
Protein synthesis requires several guanosine triphosphatase (GTPase) factors, including elongation factor Tu (EF-Tu), which delivers aminoacyl-transfer RNAs (tRNAs) to the ribosome. To understand how the ribosome triggers GTP hydrolysis in translational GTPases, we have determined the crystal structure of EF-Tu and aminoacyl-tRNA bound to the ribosome with a GTP analog, to 3.2 angstrom resolution. EF-Tu is in its active conformation, the switch I loop is ordered, and the catalytic histidine is coordinating the nucleophilic water in position for inline attack on the γ-phosphate of GTP. This activated conformation is due to a critical and conserved interaction of the histidine with A2662 of the sarcin-ricin loop of the 23S ribosomal RNA. The structure suggests a universal mechanism for GTPase activation and hydrolysis in translational GTPases on the ribosome.
MRC Laboratory of Molecular Biology, Cambridge, UK, CB2 0QH.
Rebecca M
RM
Voorhees
MRC Laboratory of Molecular Biology, Cambridge, UK, CB2 0QH.
T Martin
TM
Schmeing
MRC Laboratory of Molecular Biology, Cambridge, UK, CB2 0QH.
Ann C
AC
Kelley
MRC Laboratory of Molecular Biology, Cambridge, UK, CB2 0QH.
V
V
Ramakrishnan
D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004789:Enzyme Activation; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism*; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D009690:Nucleic Acid Conformation; D010303:Paromomycin / Q000378:metabolism; D010444:Peptide Elongation Factor Tu / Q000737:chemistry* / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism*; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D016963:Thermus thermophilus / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure
D001426:Bacterial Proteins; D010710:Phosphates; D012329:RNA, Bacterial; D012338:RNA, Ribosomal, 23S; D012346:RNA, Transfer, Amino Acyl; C011265:guanosine 5'-(beta,gamma-methylene)triphosphate; D010303:Paromomycin; D006160:Guanosine Triphosphate; D010444:Peptide Elongation Factor Tu