Insights into the functional divergence of the haloacid dehalogenase superfamily from phosphomonoesterase to inorganic pyrophosphatase

Author(s):  
Ling Yang ◽  
Yajie Lu ◽  
Weiquan Tian ◽  
Yulan Feng ◽  
Jialin Bai ◽  
...  
Biochemistry ◽  
2011 ◽  
Vol 50 (41) ◽  
pp. 8937-8949 ◽  
Author(s):  
Hua Huang ◽  
Yury Patskovsky ◽  
Rafael Toro ◽  
Jeremiah D. Farelli ◽  
Chetanya Pandya ◽  
...  

2019 ◽  
Vol 476 (16) ◽  
pp. 2297-2319 ◽  
Author(s):  
Marta Grzechowiak ◽  
Milosz Ruszkowski ◽  
Joanna Sliwiak ◽  
Kamil Szpotkowski ◽  
Michal Sikorski ◽  
...  

Abstract Inorganic pyrophosphatases (PPases, EC 3.6.1.1), which hydrolyze inorganic pyrophosphate to phosphate in the presence of divalent metal cations, play a key role in maintaining phosphorus homeostasis in cells. DNA coding inorganic pyrophosphatases from Arabidopsis thaliana (AtPPA1) and Medicago truncatula (MtPPA1) were cloned into a bacterial expression vector and the proteins were produced in Escherichia coli cells and crystallized. In terms of their subunit fold, AtPPA1 and MtPPA1 are reminiscent of other members of Family I soluble pyrophosphatases from bacteria and yeast. Like their bacterial orthologs, both plant PPases form hexamers, as confirmed in solution by multi-angle light scattering and size-exclusion chromatography. This is in contrast with the fungal counterparts, which are dimeric. Unexpectedly, the crystallized AtPPA1 and MtPPA1 proteins lack ∼30 amino acid residues at their N-termini, as independently confirmed by chemical sequencing. In vitro, self-cleavage of the recombinant proteins is observed after prolonged storage or during crystallization. The cleaved fragment corresponds to a putative signal peptide of mitochondrial targeting, with a predicted cleavage site at Val31–Ala32. Site-directed mutagenesis shows that mutations of the key active site Asp residues dramatically reduce the cleavage rate, which suggests a moonlighting proteolytic activity. Moreover, the discovery of autoproteolytic cleavage of a mitochondrial targeting peptide would change our perception of this signaling process.


1972 ◽  
Vol 70 (4) ◽  
pp. 676-682 ◽  
Author(s):  
Cipora Streifler ◽  
Arie Orenstein ◽  
Arieh Harell

ABSTRACT The influence of thyrocalcitonin (TCT) on the enzymes alkaline phosphatase and inorganic pyrophosphatase in rat bone, kidney and intestine was studied. The rats were injected with TCT every hour for 4 hours. They were divided into groups and were sacrificed 1 h after the first, second, third and fourth injection respectively. The plasma calcium was found to be reduced. Enzyme studies showed that: a) in tibia metaphysis homogenates alkaline phosphatase increased in response to TCT, to 198, 175, 154 and 183 per cent of the non-injected rats after 1, 2, 3, and 4 injections, respectively; inorganic pyrophosphatase was elevated to 356, 209, 221, 425 per cent after the same TCT injections. b) In kidney homogenates alkaline phosphatase was reduced to 75, 53, 79, 68 per cent of the non-injected rats after 1, 2, 3 and four doses, respectively; inorganic pyrophosphatase was reduced to 78, 56, 77 and 71 per cent after the same injections of TCT. c) In the jejunum, alkaline phosphatase was found to be 88.5, 71, 91 and 115 per cent of the untreated rats after 1, 2, 3 and 4 injections, respectively; pyrophosphatase in this tissue was found to be 105, 102, 102 and 113 per cent of the normal under the above conditions. The results indicate: 1. TCT causes increases in alkaline phosphatase and inorganic pyrophosphatase activities in bone. The increase of pyrophosphatase is significantly more marked than the increase of alkaline phosphatase; 2. in kidney tissue, the action of TCT on these two enzymes is slower and their activities are equally reduced; 3. in the jejunum no significant effect of TCT on the activity of these two enzymes was observed.


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