1asz

[[Image:1asz.gif|left|200px]]

|PDB= 1asz |SIZE=350|CAPTION= <scene name='initialview01'>1asz</scene>, resolution 3.0&Aring;

|SITE=

|LIGAND= <scene name='pdbligand=1MG:1N-METHYLGUANOSINE-5&#39;-MONOPHOSPHATE'>1MG</scene>, <scene name='pdbligand=5MC:5-METHYLCYTIDINE-5&#39;-MONOPHOSPHATE'>5MC</scene>, <scene name='pdbligand=5MU:5-METHYLURIDINE+5&#39;-MONOPHOSPHATE'>5MU</scene>, <scene name='pdbligand=A:ADENOSINE-5&#39;-MONOPHOSPHATE'>A</scene>, <scene name='pdbligand=ATP:ADENOSINE-5&#39;-TRIPHOSPHATE'>ATP</scene>, <scene name='pdbligand=C:CYTIDINE-5&#39;-MONOPHOSPHATE'>C</scene>, <scene name='pdbligand=G:GUANOSINE-5&#39;-MONOPHOSPHATE'>G</scene>, <scene name='pdbligand=H2U:5,6-DIHYDROURIDINE-5&#39;-MONOPHOSPHATE'>H2U</scene>, <scene name='pdbligand=PSU:PSEUDOURIDINE-5&#39;-MONOPHOSPHATE'>PSU</scene>, <scene name='pdbligand=U:URIDINE-5&#39;-MONOPHOSPHATE'>U</scene>

|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Aspartate--tRNA_ligase Aspartate--tRNA ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.1.1.12 6.1.1.12] </span>

|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1asz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1asz OCA], [http://www.ebi.ac.uk/pdbsum/1asz PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1asz RCSB]</span>

 

 

==Overview==

The crystal structures of the various complexes formed by yeast aspartyl-tRNA synthetase (AspRS) and its substrates provide snapshots of the active site corresponding to different steps of the aminoacylation reaction. Native crystals of the binary complex tRNA-AspRS were soaked in solutions containing the two other substrates, ATP (or its analog AMPPcP) and aspartic acid. When all substrates are present in the crystal, this leads to the formation of the aspartyl-adenylate and/or the aspartyl-tRNA. A class II-specific pathway for the aminoacylation reaction is proposed which explains the known functional differences between the two classes while preserving a common framework. Extended signature sequences characteristic of class II aaRS (motifs 2 and 3) constitute the basic functional unit. The ATP molecule adopts a bent conformation, stabilized by the invariant Arg531 of motif 3 and a magnesium ion coordinated to the pyrophosphate group and to two class-invariant acidic residues. The aspartic acid substrate is positioned by a class II invariant acidic residue, Asp342, interacting with the amino group and by amino acids conserved in the aspartyl synthetase family. The amino acids in contact with the substrates have been probed by site-directed mutagenesis for their functional implication.

 

1ASZ is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. The following page contains interesting information on the relation of 1ASZ with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb16_1.html Aminoacyl-tRNA Synthetases]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ASZ OCA].

 

The active site of yeast aspartyl-tRNA synthetase: structural and functional aspects of the aminoacylation reaction., Cavarelli J, Eriani G, Rees B, Ruff M, Boeglin M, Mitschler A, Martin F, Gangloff J, Thierry JC, Moras D, EMBO J. 1994 Jan 15;13(2):327-37. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8313877 8313877]

[[Category: Aspartate--tRNA ligase]]

[[Category: Cavarelli, J.]]

[[Category: Moras, D.]]

[[Category: Rees, B.]]

[[Category: Thierry, J C.]]