View source for 6j27


==Crystal structure of the branched-chain polyamine synthase from Thermus thermophilus (Tth-BpsA) in complex with N4-aminopropylspermidine and 5'-methylthioadenosine==
<StructureSection load='6j27' size='340' side='right'caption='[[6j27]], [[Resolution|resolution]] 1.66&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6j27]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_thermophilus_HB27 Thermus thermophilus HB27]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6J27 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6J27 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.66&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE:FE+(III)+ION'>FE</scene>, <scene name='pdbligand=MTA:5-DEOXY-5-METHYLTHIOADENOSINE'>MTA</scene>, <scene name='pdbligand=N4P:N,N-bis(3-aminopropyl)butane-1,4-diamine'>N4P</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene>, <scene name='pdbligand=PGE:TRIETHYLENE+GLYCOL'>PGE</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=6j27 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6j27 OCA], [https://pdbe.org/6j27 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6j27 RCSB], [https://www.ebi.ac.uk/pdbsum/6j27 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6j27 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q72L89_THET2 Q72L89_THET2] Involved in the biosynthesis of branched-chain polyamines, which support the growth of thermophiles under high-temperature conditions. Catalyzes the sequential condensation of spermidine with the aminopropyl groups of decarboxylated S-adenosylmethionines to produce N(4)-bis(aminopropyl)spermidine via N(4)-aminopropylspermidine.[HAMAP-Rule:MF_01947]
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Branched-chain polyamine synthase (BpsA) catalyzes sequential aminopropyl transfer from the donor, decarboxylated S-adenosylmethionine (dcSAM), to the acceptor, linear-chain polyamine, resulting in the production of a quaternary-branched polyamine via tertiary branched polyamine intermediates. Here, we analyzed the catalytic properties and X-ray crystal structure of Tth-BpsA from Thermus thermophilus and compared them with those of Tk-BpsA from Thermococcus kodakarensis, which revealed differences in acceptor substrate specificity and C-terminal structure between these two enzymes. To investigate the role of the C-terminal flexible region in acceptor recognition, a region (QDEEATTY) in Tth-BpsA was replaced with that in Tk-BpsA (YDDEESSTT) to create chimeric Tth-BpsA C9, which showed a severe reduction in catalytic efficiency toward N(4) -aminopropylnorspermidine, but not toward N(4) -aminopropylspermidine, mimicking Tk-BpsA substrate specificity. Tth-BpsA C9 Tyr(346) and Thr(354) contributed to discrimination between tertiary branched-chain polyamine substrates, suggesting that the C-terminal region of BpsA recognizes acceptor substrates. Liquid chromatography-tandem mass spectrometry analysis on a Tk-BpsA reaction mixture with dcSAM revealed two aminopropyl groups bound to two of five aspartate/glutamate residues (Glu(339) , Asp(342) , Asp(343) , Glu(344) , and Glu(345) ) in the C-terminal flexible region. Mutating each of these five amino acid residues to asparagine/glutamine resulted in a slight decrease in activity. The quadruple mutant D342N/D343N/E344Q/E345Q exhibited a severe reduction in catalytic efficiency, suggesting that these aspartate/glutamate residues function to receive aminopropyl chains. In addition, the X-ray crystal structure of the Tk-BpsA ternary complex bound to N(4) -bis(aminopropyl)spermidine revealed that Asp(126) and Glu(259) interacted with the aminopropyl moiety in N(4) -aminopropylspermidine.

The C-terminal flexible region of branched-chain polyamine synthase facilitates substrate specificity and catalysis.,Hidese R, Toyoda M, Yoshino KI, Fukuda W, Wihardja GA, Kimura S, Fujita J, Niitsu M, Oshima T, Imanaka T, Mizohata E, Fujiwara S FEBS J. 2019 Jun 4. doi: 10.1111/febs.14949. PMID:31162806<ref>PMID:31162806</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6j27" style="background-color:#fffaf0;"></div>

==See Also==
*[[Spermidine synthase 3D structures|Spermidine synthase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermus thermophilus HB27]]
[[Category: Fujita J]]
[[Category: Inoue T]]
[[Category: Mizohata E]]
[[Category: Toyoda M]]