The origin of the high sensitivity of muscle fructose 1,6‐bisphosphatase towards AMP

Rakus, Dariusz; Maciaszczyk, Ewa; Wawrzycka, Donata; Ułaszewski, Stanisław; Eschrich, Klaus; Dżugaj, Andrzej

doi:10.1016/j.febslet.2005.09.021

Cited by 10 publications

(11 citation statements)

References 32 publications

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“…Gizak et al (2008) presented evidence that truncation starting from Pro5 at the N-terminus decreased the sensitivity of muscle FBPase towards AMP. Rakus et al (2005) found that the three-point mutant K20E/T177M/Q179C was inhibited by AMP about 26 times more weakly than the wild-type muscle isozyme. They also constructed two chimeric human FBPases (L50M288 and M50L288; Rakus et al, 2003) in which the N-terminal residues (1-50) were derived from the other isozyme.…”

Section: Discussionmentioning

confidence: 97%

Structure of E69Q mutant of human muscle fructose-1,6-bisphosphatase

Zarzycki

Kolodziejczyk

Maciaszczyk-Dziubińska

et al. 2011

Acta Crystallogr D Biol Cryst

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Human fructose-1,6-bisphosphatase is an allosteric enzyme that is regulated by different ligands. There are only two known isozymes in human tissues: the liver isozyme (the key enzyme of gluconeogenesis), which is regulated by fructose 2,6-bisphosphate, and its muscle counterpart (participating in glycogen synthesis), which is regulated by calcium ions. AMP, which is an allosteric inhibitor of both isozymes, inhibits the muscle isozyme with an I(0.5) that is 35-100 times lower than for the liver isozyme and the reason for this difference remains obscure. In studies aiming at an explanation of the main differences in the regulation of the two isozymes, it has been shown that only one residue, in position 69, regulates the sensitivity towards calcium ions. As a consequence of this finding, an E69Q mutant of the muscle isozyme, which is insensitive to calcium ions while retaining all other kinetic properties resembling the liver isozyme, has been prepared and crystallized. Here, two crystal structures of this mutant enzyme in complex with AMP with and without fructose 6-phosphate (the product of the catalytic reaction) are presented. The AMP binding pattern of the muscle isozyme is quite similar to that of the liver isozyme and the T conformations of the two isozymes are nearly the same.

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Section: Discussionmentioning

confidence: 97%

Structure of E69Q mutant of human muscle fructose-1,6-bisphosphatase

Zarzycki

Kolodziejczyk

Maciaszczyk-Dziubińska

et al. 2011

Acta Crystallogr D Biol Cryst

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“…The liver FBPase is recognized as the regulatory enzyme of gluconeogenesis [53], and high FBPase level is regarded as a way to speed up the production of ATP in order to resist ROS. In our study, MP resulted in an increased expression of FBPase, and we propose that the overexpression of FBPase participated in relieving ROS induced by MP.…”

Section: Mp Induction Of Differentially Expressed Proteins Involved Imentioning

confidence: 99%

Proteomic analysis of methyl parathion-responsive proteins in Sparus latus liver

Chen

Huang

2011

Fish & Shellfish Immunology

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“…, the higher affinity (10–100 times lower I 0.5 , i.e. , the inhibitor concentration which causes 50% reduction of the enzyme catalysis) for AMP than either the liver or kidney enzymes [22]–[26]. Recent kinetic studies on mutant forms of human muscle and liver Fru-1,6-Pase indicated that Lys20 plays a pivotal role in the high affinity of human muscle Fru-1,6-Pase (hmFru-1,6-Pase) for AMP [25], [26].…”

Section: Introductionmentioning

confidence: 99%

“…, the inhibitor concentration which causes 50% reduction of the enzyme catalysis) for AMP than either the liver or kidney enzymes [22]–[26]. Recent kinetic studies on mutant forms of human muscle and liver Fru-1,6-Pase indicated that Lys20 plays a pivotal role in the high affinity of human muscle Fru-1,6-Pase (hmFru-1,6-Pase) for AMP [25], [26]. A comparison of the homology between Fru-1,6-pase from human muscle and human liver revealed that they share 77% sequence identity, and that muscle Fru-1,6-Pase must be encoded by a separate gene [23].…”

Section: Introductionmentioning

confidence: 99%

Crystal Structures of Human Muscle Fructose-1,6-Bisphosphatase: Novel Quaternary States, Enhanced AMP Affinity, and Allosteric Signal Transmission Pathway

et al. 2013

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Fructose-1,6-bisphosphatase, a key enzyme in gluconeogenesis, is subject to metabolic regulation. The human muscle isozyme is significantly more sensitive towards the allosteric inhibitor, AMP, than the liver isoform. Here we report crystal structures and kinetic studies for wild-type human muscle Fru-1,6-Pase, the AMP-bound (1.6 Å), and product-bound complexes of the Q32R mutant, which was firstly introduced by an error in the cloning. Our high-resolution structure reveals for the first time that the higher sensitivity of the muscle isozyme towards AMP originates from an additional water-mediated, H-bonded network established between AMP and the binding pocket. Also present in our structures are a metaphosphate molecule, alternate conformations of Glu97 coordinating Mg2+, and possible metal migration during catalysis. Although the individual subunit is similar to previously reported Fru-1,6-Pase structures, the tetrameric assembly of all these structures deviates from the canonical R- or T-states, representing novel tetrameric assemblies. Intriguingly, the concentration of AMP required for 50% inhibition of the Q32R mutant is increased 19-fold, and the cooperativity of both AMP and Mg2+ is abolished or decreased. These structures demonstrate the Q32R mutation affects the conformations of both N-terminal residues and the dynamic loop 52–72. Also importantly, structural comparison indicates that this mutation in helix α2 is detrimental to the R-to-T conversion as evidenced by the absence of quaternary structural changes upon AMP binding, providing direct evidence for the critical role of helix α2 in the allosteric signal transduction.

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The origin of the high sensitivity of muscle fructose 1,6‐bisphosphatase towards AMP

Cited by 10 publications

References 32 publications

Structure of E69Q mutant of human muscle fructose-1,6-bisphosphatase

Structure of E69Q mutant of human muscle fructose-1,6-bisphosphatase

Proteomic analysis of methyl parathion-responsive proteins in Sparus latus liver

Crystal Structures of Human Muscle Fructose-1,6-Bisphosphatase: Novel Quaternary States, Enhanced AMP Affinity, and Allosteric Signal Transmission Pathway

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