The domain within your query sequence starts at position 316 and ends at position 365; the E-value for the tRNA_SAD domain shown below is 1.26e-16.

TTVYRCGPLIDLCKGPHVRHTGKIKAIKIFKNSSTYWEGNPEMETLQRIY

tRNA_SAD

Threonyl and Alanyl tRNA synthetase second additional domain

• SMART accession number: SM00863
• Description: The catalytically active form of threonyl/alanyl tRNA synthetase is a dimer. Within the tRNA synthetase class II dimer, the bound tRNA interacts with both monomers making specific interactions with the catalytic domain, the C-terminal domain, and this SAD domain (the second additional domain). The second additional domain is comprised of a pair of perpendicularly orientated antiparallel beta sheets, of four and three strands, respectively, that surround a central alpha helix that forms the core of the domain.
• Interpro abstract (IPR012947):

  The catalytically active form of threonyl/alanyl tRNA synthetase is a dimer. Within the tRNA synthetase class II dimer, the bound tRNA interacts with both monomers making specific interactions with the catalytic domain, the C-terminal domain, and this SAD domain (the second additional domain). The second additional domain is comprised of a pair of perpendicularly orientated antiparallel beta sheets, of four and three strands, respectively, that surround a central alpha helix that forms the core of the domain [ (PUBMED:10319817) ].

• GO process: tRNA aminoacylation (GO:0043039)
• GO function: ATP binding (GO:0005524), aminoacyl-tRNA ligase activity (GO:0004812)

There are 57173 tRNA_SAD domains in 57163 proteins in SMART's nrdb database.

Cellular role (predicted cellular role)

Cellular role: translation

Literature (relevant references for this domain)

Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.

• Sankaranarayanan R et al.
• The structure of threonyl-tRNA synthetase-tRNA(Thr) complex enlightens itsrepressor activity and reveals an essential zinc ion in the active site.
• Cell. 1999; 97: 371-81

E. coli threonyl-tRNA synthetase (ThrRS) is a class II enzyme thatrepresses the translation of its own mRNA. We report the crystal structureat 2.9 A resolution of the complex between tRNA(Thr) and ThrRS, whosestructural features reveal novel strategies for providing specificity intRNA selection. These include an amino-terminal domain containing a novelprotein fold that makes minor groove contacts with the tRNA acceptor stem.The enzyme induces a large deformation of the anticodon loop, resulting inan interaction between two adjacent anticodon bases, which accounts fortheir prominent role in tRNA identity and translational regulation. A zincion found in the active site is implicated in amino acidrecognition/discrimination.

Structure (3D structures containing this domain)

3D Structures of tRNA_SAD domains in PDB

PDB code	Title
1nyq	Structure of Staphylococcus aureus threonyl-tRNA synthetase complexed with an analogue of threonyl adenylate
1nyr	Structure of Staphylococcus aureus threonyl-tRNA synthetase complexed with ATP
1qf6	STRUCTURE OF E. COLI THREONYL-TRNA SYNTHETASE COMPLEXED WITH ITS COGNATE TRNA
1tje	Crystal structure of the editing domain of threonyl-tRNA synthetase
1tke	Crystal structure of the editing domain of threonyl-tRNA synthetase complexed with serine
1tkg	Crystal structure of the editing domain of threonyl-tRNA synthetase complexed with an analog of seryladenylate
1tky	Crystal structure of the editing domain of threonyl-tRNA synthetase complexed with seryl-3'-aminoadenosine
2e1b	Crystal structure of the AlaX-M trans-editing enzyme from Pyrococcus horikoshii
2ztg	Crystal structure of Archaeoglobus fulgidus alanyl-tRNA synthetase lacking the C-terminal dimerization domain in complex with Ala-SA
2zze	Crystal structure of alanyl-tRNA synthetase without oligomerization domain in lysine-methylated form
2zzf	Crystal structure of alanyl-tRNA synthetase without oligomerization domain
2zzg	Crystal structure of alanyl-tRNA synthetase in complex with 5''-O-(N-(L-alanyl)-sulfamyoxyl) adenine without oligomerization domain
3kew	Crystal structure of probable alanyl-trna-synthase from Clostridium perfringens
3wqy	3WQY
3wqz	3WQZ

Links (links to other resources describing this domain)

• INTERPRO: IPR012947
• PFAM: tRNA_SAD