scholarly journals Protein moonlighting elucidates the essential human pathway catalyzing lipoic acid assembly on its cognate enzymes

2018 ◽  
Vol 115 (30) ◽  
pp. E7063-E7072 ◽  
Author(s):  
Xinyun Cao ◽  
Lei Zhu ◽  
Xuejiao Song ◽  
Zhe Hu ◽  
John E. Cronan
Keyword(s):  
Lipoic Acid ◽  
Metabolic Disorders ◽  
Enzyme Level ◽  
Early Death ◽  
Glycine Cleavage System ◽  
Amino Acid Degradation ◽  
Group Assembly ◽  
Glycine Cleavage ◽  
Assembly Map ◽  
H Protein

The lack of attachment of lipoic acid to its cognate enzyme proteins results in devastating human metabolic disorders. These mitochondrial disorders are evident soon after birth and generally result in early death. The mutations causing specific defects in lipoyl assembly map in three genes, LIAS, LIPT1, and LIPT2. Although physiological roles have been proposed for the encoded proteins, only the LIPT1 protein had been studied at the enzyme level. LIPT1 was reported to catalyze only the second partial reaction of the classical lipoate ligase mechanism. We report that the physiologically relevant LIPT1 enzyme activity is transfer of lipoyl moieties from the H protein of the glycine cleavage system to the E2 subunits of the 2-oxoacid dehydrogenases required for respiration (e.g., pyruvate dehydrogenase) and amino acid degradation. We also report that LIPT2 encodes an octanoyl transferase that initiates lipoyl group assembly. The human pathway is now biochemically defined.

scholarly journals Development and retention of a primordial moonlighting pathway of protein modification in the absence of selection presents a puzzle

2018 ◽  
Vol 115 (4) ◽  
pp. 647-655 ◽  
Author(s):  
Xinyun Cao ◽  
Yaoqin Hong ◽  
Lei Zhu ◽  
Yuanyuan Hu ◽  
John E. Cronan
Keyword(s):  
Lipoic Acid ◽  
Protein Modification ◽  
Acid Synthesis ◽  
Covalent Attachment ◽  
Aquifex Aeolicus ◽  
Original Function ◽  
E Coli ◽  
Metabolism Enzymes ◽  
Glycine Cleavage ◽  
H Protein

Lipoic acid is synthesized by a remarkably atypical pathway in which the cofactor is assembled on its cognate proteins. An octanoyl moiety diverted from fatty acid synthesis is covalently attached to the acceptor protein, and sulfur insertion at carbons 6 and 8 of the octanoyl moiety form the lipoyl cofactor. Covalent attachment of this cofactor is required for function of several central metabolism enzymes, including the glycine cleavage H protein (GcvH). InBacillus subtilis, GcvH is the sole substrate for lipoate assembly. Hence lipoic acid-requiring 2-oxoacid dehydrogenase (OADH) proteins acquire the cofactor only by transfer from lipoylated GcvH. Lipoyl transfer has been argued to be the primordial pathway of OADH lipoylation. TheEscherichia colipathway where lipoate is directly assembled on both its GcvH and OADH proteins, is proposed to have arisen later. Because roughly 3 billion years separate the divergence of these bacteria, it is surprising thatE. coliGcvH functionally substitutes for theB. subtilisprotein in lipoyl transfer. Known and putative GcvHs from other bacteria and eukaryotes also substitute forB. subtilisGcvH in OADH modification. Because glycine cleavage is the primary GcvH role in ancestral bacteria that lack OADH enzymes, lipoyl transfer is a “moonlighting” function: that is, development of a new function while retaining the original function. This moonlighting has been conserved in the absence of selection by some, but not all, GcvH proteins. Moreover,Aquifex aeolicusencodes five putative GcvHs, two of which have the moonlighting function, whereas others function only in glycine cleavage.

scholarly journals Synthesis and Characterization of Selenolipoylated H-protein of the Glycine Cleavage System

1997 ◽  
Vol 272 (32) ◽  
pp. 19880-19883 ◽  
Author(s):  
Kazuko Fujiwara ◽  
Kazuko Okamura-Ikeda ◽  
Lester Packer ◽  
Yutaro Motokawa
Keyword(s):  
Synthesis And Characterization ◽  
Glycine Cleavage System ◽  
Glycine Cleavage ◽  
H Protein

scholarly journals Overexpressing the H-protein of the glycine cleavage system increases biomass yield in glasshouse and field-grown transgenic tobacco plants

2018 ◽  
Vol 17 (1) ◽  
pp. 141-151 ◽  
Author(s):  
Patricia E. López-Calcagno ◽  
Stuart Fisk ◽  
Kenny L. Brown ◽  
Simon E. Bull ◽  
Paul F. South ◽  
...  
Keyword(s):  
Transgenic Tobacco ◽  
Biomass Yield ◽  
Transgenic Tobacco Plants ◽  
Glycine Cleavage System ◽  
Tobacco Plants ◽  
Glycine Cleavage ◽  
H Protein

scholarly journals Formaldehyde formation in the glycine cleavage system and its use for an aldolase-based biosynthesis of 1,3-prodanediol

2020 ◽  
Author(s):  
Yingying Xu ◽  
Hao Meng ◽  
Jie Ren ◽  
An-Ping Zeng
Keyword(s):  
Release Rate ◽  
Metabolic Pathway ◽  
Protein Concentration ◽  
Biosynthetic Pathway ◽  
Oxidative Degradation ◽  
Glycine Cleavage System ◽  
Speed Up ◽  
Glycine Cleavage ◽  
H Protein

Abstract Glycine cleavage system (GCS) occupies a key position in one-carbon (C1) metabolic pathway and receives great attention for the use of C1 carbons like formate and CO2 via synthetic biology. In this work, we demonstrate that formaldehyde exists as a substantial byproduct of the GCS reaction cycle. Three causes are identified for its formation. First, the principal one is the decomposition of N5,N10-methylene-tetrahydrofolate (5,10-CH2-THF) to form formaldehyde and THF. Increasing the rate of glycine cleavage promotes the formation of 5,10-CH2-THF, thereby increasing the formaldehyde release rate. Next, formaldehyde can be produced in the GCS even in the absence of THF. The reason is that T-protein of the GCS can degrade methylamine-loaded H-protein (Hint) to formaldehyde and ammonia, accompanied with the formation of dihydrolipoyl H-protein (Hred), but the reaction rate is less than 0.16% of that in the presence of THF. Increasing T-protein concentration can speed up the release rate of formaldehyde by Hint. Finally, a certain amount of formaldehyde can be formed in the GCS due to oxidative degradation of THF. Based on a formaldehyde-dependent aldolase, we elaborated a glycine-based one carbon metabolic pathway for the biosynthesis of 1,3-propanediol (1,3-PDO) in vitro. This work provides quantitative data and mechanistic understanding of formaldehyde formation in the GCS and a new biosynthetic pathway of 1,3-PDO.

scholarly journals Formaldehyde formation in the glycine cleavage system and its use for an aldolase-based biosynthesis of 1,3-prodanediol

2020 ◽  
Author(s):  
Yingying Xu ◽  
Hao Meng ◽  
Jie Ren ◽  
An-Ping Zeng
Keyword(s):  
Release Rate ◽  
Metabolic Pathway ◽  
Protein Concentration ◽  
Biosynthetic Pathway ◽  
Oxidative Degradation ◽  
Glycine Cleavage System ◽  
Speed Up ◽  
Glycine Cleavage ◽  
H Protein

Abstract Glycine cleavage system (GCS) occupies a key position in one-carbon (C1) metabolic pathway and receives great attention for the use of C1 carbons like formate and CO2 via synthetic biology. In this work, we demonstrate that formaldehyde exists as a substantial byproduct of the GCS reaction cycle. Three causes are identified for its formation. First, the principal one is the decomposition of N5,N10-methylene-tetrahydrofolate (5,10-CH2-THF) to form formaldehyde and THF. Increasing the rate of glycine cleavage promotes the formation of 5,10-CH2-THF, thereby increasing the formaldehyde release rate. Next, formaldehyde can be produced in the GCS even in the absence of THF. The reason is that T-protein of the GCS can degrade methylamine-loaded H-protein (Hint) to formaldehyde and ammonia, accompanied with the formation of dihydrolipoyl H-protein (Hred), but the reaction rate is less than 0.16% of that in the presence of THF. Increasing T-protein concentration can speed up the release rate of formaldehyde by Hint. Finally, a certain amount of formaldehyde can be formed in the GCS due to oxidative degradation of THF. Based on a formaldehyde-dependent aldolase, we elaborated a glycine-based one carbon metabolic pathway for the biosynthesis of 1,3-propanediol (1,3-PDO) in vitro. This work provides quantitative data and mechanistic understanding of formaldehyde formation in the GCS and a new biosynthetic pathway of 1,3-PDO.

scholarly journals Crystal structure of T-H protein complex of the glycine cleavage system

2011 ◽  
Vol 67 (a1) ◽  
pp. C434-C435
Author(s):  
K. Okamura-Ikeda ◽  
H. Hosaka ◽  
N. Maita ◽  
K. Fujiwara ◽  
A. C. Yoshizawa ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Protein Complex ◽  
Glycine Cleavage System ◽  
Glycine Cleavage ◽  
H Protein

scholarly journals High-Resolution X-ray Crystallography Studies of the H-Protein of Glycine Cleavage System

2008 ◽  
Vol S2 (01) ◽  
pp. 286-286
Author(s):  
A. Nakagawa ◽  
A. Higashiura ◽  
T. Kurakane ◽  
M. Matsuda ◽  
M. Suzuki ◽  
...  
Keyword(s):  
High Resolution ◽  
Glycine Cleavage System ◽  
X Ray ◽  
X Ray Crystallography ◽  
Glycine Cleavage ◽  
H Protein
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