scholarly journals Insight into Coenzyme A cofactor binding and the mechanism of acyl-transfer in an acylating aldehyde dehydrogenase from Clostridium phytofermentans

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Laura R. Tuck ◽  
Kirsten Altenbach ◽  
Thiau Fu Ang ◽  
Adam D. Crawshaw ◽  
Dominic J. Campopiano ◽  
...  
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Coenzyme A ◽  
Acyl Transfer ◽  
Cofactor Binding ◽  
Insight Into ◽  
Clostridium Phytofermentans

scholarly journals Mitochondrial ClpX activates an essential biosynthetic enzyme through partial unfolding

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Julia R Kardon ◽  
Jamie A Moroco ◽  
John R Engen ◽  
Tania A Baker
Keyword(s):  
Active Site ◽  
Autonomous System ◽  
Aminolevulinic Acid ◽  
Structural Features ◽  
Biosynthetic Enzyme ◽  
Cofactor Binding ◽  
Partial Unfolding ◽  
Chaperone Interactions ◽  
Aaa Protein ◽  
Insight Into

Mitochondria control the activity, quality, and lifetime of their proteins with an autonomous system of chaperones, but the signals that direct substrate-chaperone interactions and outcomes are poorly understood. We previously discovered that the mitochondrial AAA+ protein unfoldase ClpX (mtClpX) activates the initiating enzyme for heme biosynthesis, 5-aminolevulinic acid synthase (ALAS), by promoting cofactor incorporation. Here, we ask how mtClpX accomplishes this activation. Using S. cerevisiae proteins, we identified sequence and structural features within ALAS that position mtClpX and provide it with a grip for acting on ALAS. Observation of ALAS undergoing remodeling by mtClpX revealed that unfolding is limited to a region extending from the mtClpX-binding site to the active site. Unfolding along this path is required for mtClpX to gate cofactor binding to ALAS. This targeted unfolding contrasts with the global unfolding canonically executed by ClpX homologs and provides insight into how substrate-chaperone interactions direct the outcome of remodeling.

Crystal Structure and Amide H/D Exchange of Binary Complexes of Alcohol Dehydrogenase fromBacillus stearothermophilus:  Insight into Thermostability and Cofactor Binding†,‡

Biochemistry ◽  
2004 ◽  
Vol 43 (18) ◽  
pp. 5266-5277 ◽  
Author(s):  
Christopher Ceccarelli ◽  
Zhao-Xun Liang ◽  
Michael Strickler ◽  
Gerd Prehna ◽  
Barry M. Goldstein ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Alcohol Dehydrogenase ◽  
Cofactor Binding ◽  
Binary Complexes ◽  
Insight Into

scholarly journals Identification of Dephospho-Coenzyme A (Dephospho-CoA) Kinase in Thermococcus kodakarensis and Elucidation of the Entire CoA Biosynthesis Pathway in Archaea

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Takahiro Shimosaka ◽  
Kira S. Makarova ◽  
Eugene V. Koonin ◽  
Haruyuki Atomi
Keyword(s):  
Metabolic Pathways ◽  
Coenzyme A ◽  
Protein A ◽  
Biosynthesis Pathway ◽  
Content Type ◽  
Hyperthermophilic Archaeon ◽  
Thermococcus Kodakarensis ◽  
Uncharacterized Gene ◽  
Wide Range ◽  
Insight Into

ABSTRACT Dephospho-coenzyme A (dephospho-CoA) kinase (DPCK) catalyzes the ATP-dependent phosphorylation of dephospho-CoA, the final step in coenzyme A (CoA) biosynthesis. DPCK has been identified and characterized in bacteria and eukaryotes but not in archaea. The hyperthermophilic archaeon Thermococcus kodakarensis encodes two homologs of bacterial DPCK and the DPCK domain of eukaryotic CoA synthase, TK1334 and TK2192. We purified the recombinant TK1334 and TK2192 proteins and found that they lacked DPCK activity. Bioinformatic analyses showed that, in several archaea, the uncharacterized gene from arCOG04076 protein is fused with the gene for phosphopantetheine adenylyltransferase (PPAT), which catalyzes the reaction upstream of the DPCK reaction in CoA biosynthesis. This observation suggested that members of arCOG04076, both fused to PPAT and standalone, could be the missing archaeal DPCKs. We purified the recombinant TK1697 protein, a standalone member of arCOG04076 from T. kodakarensis, and demonstrated its GTP-dependent DPCK activity. Disruption of the TK1697 resulted in CoA auxotrophy, indicating that TK1697 encodes a DPCK that contributes to CoA biosynthesis in T. kodakarensis. TK1697 homologs are widely distributed in archaea, suggesting that the arCOG04076 protein represents a novel family of DPCK that is not homologous to bacterial and eukaryotic DPCKs but is distantly related to bacterial and eukaryotic thiamine pyrophosphokinases. We also constructed and characterized gene disruption strains of TK0517 and TK2128, homologs of bifunctional phosphopantothenoylcysteine synthetase-phosphopantothenoylcysteine decarboxylase and PPAT, respectively. Both strains displayed CoA auxotrophy, indicating their contribution to CoA biosynthesis. Taken together with previous studies, the results experimentally validate the entire CoA biosynthesis pathway in T. kodakarensis. IMPORTANCE CoA is utilized in a wide range of metabolic pathways, and its biosynthesis is essential for all life. Pathways for CoA biosynthesis in bacteria and eukaryotes have been established. In archaea, however, the enzyme that catalyzes the final step in CoA biosynthesis, dephospho-CoA kinase (DPCK), had not been identified. In the present study, bioinformatic analyses identified a candidate for the DPCK in archaea, which was biochemically and genetically confirmed in the hyperthermophilic archaeon Thermococcus kodakarensis. Genetic analyses on genes presumed to encode bifunctional phosphopantothenoylcysteine synthetase-phosphopantothenoylcysteine decarboxylase and phosphopantetheine adenylyltransferase confirmed their involvement in CoA biosynthesis. Taken together with previous studies, the results reveal the entire pathway for CoA biosynthesis in a single archaeon and provide insight into the different mechanisms of CoA biosynthesis and their distribution in nature.

scholarly journals Structural basis for catalysis and substrate specificity of human ACAT1

2020 ◽  
Author(s):  
Hongwu Qian ◽  
Xin Zhao ◽  
Renhong Yan ◽  
Shuai Gao ◽  
Xue Sun ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Coenzyme A ◽  
Cholesterol Metabolism ◽  
Acyl Chain ◽  
Acyl Transfer ◽  
Structural Basis ◽  
Lateral Entry ◽  
Transmembrane Segments ◽  
Close Relationship ◽  
Acyl Coenzyme A

SummaryAcyl-coenzyme A: cholesterol acyltransferases (ACATs) catalyze acyl transfer from acyl-coenzyme A (CoA) to cholesterol to generate cholesteryl ester, which is the primary form for cellular storage and plasma transport of cholesterol. Because of their close relationship with cholesterol metabolism, ACATs represent potential drug target for the treatment of atherosclerosis and other cholesterol-related disorders. Here we present the cryo-EM structure of human ACAT1 at 3.3 Å resolution for dimer of dimers and 3.0 Å for a dimer. Each protomer consists of nine transmembrane segments that enclose a cytosolic (C) and a transmembrane (T) tunnel. The tunnels, each accommodating an elongated density, converge at the predicted catalytic site. Structure-guided mutational analyses suggest the cytosolic and lateral entry for acyl-CoA and cholesterol, respectively. Our structural, biochemical, and mass spectrometric characterizations reveal the catalytic mechanism and substrate preference for unsaturated acyl chain by ACAT1.

Nitrite inhibition of acyl transfer by coenzyme A via the formation of an S-nitrosothiol derivative

1984 ◽  
Vol 32 (5) ◽  
pp. 1057-1060 ◽  
Author(s):  
Shu I Tu ◽  
D. Michael Byler ◽  
James R. Cavanaugh
Keyword(s):  
Coenzyme A ◽  
Acyl Transfer ◽  
Nitrite Inhibition
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