Characterization of the magnesium chelatase from Thermosynechococcus elongatus

2013 ◽  
Vol 457 (1) ◽  
pp. 163-170 ◽  
Author(s):  
Nathan B. P. Adams ◽  
Christopher J. Marklew ◽  
Amanda A. Brindley ◽  
C. Neil Hunter ◽  
James D. Reid
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Thermostable Enzyme ◽  
Enzyme Complex ◽  
Magnesium Chelatase

Magnesium chelatase is the ‘gatekeeper’ multi-subunit enzyme complex that initiates chlorophyll biosynthesis; we present the first characterization of an active thermostable enzyme complex and we use hybrid mesophilic/thermophilic chelatase complexes to reveal that Mg2+ co-operativity resides in the ChlD subunit.

scholarly journals Interaction Between Induced and Natural Variation at oil yellow1 Delays Reproductive Maturity in Maize

2019 ◽  
Vol 10 (2) ◽  
pp. 797-810
Author(s):  
Rajdeep S. Khangura ◽  
Bala P. Venkata ◽  
Sandeep R. Marla ◽  
Michael V. Mickelbart ◽  
Singha Dhungana ◽  
...  
Keyword(s):  
Flowering Time ◽  
Chlorophyll Content ◽  
Chlorophyll Biosynthesis ◽  
Wild Type ◽  
Reproductive Maturity ◽  
Magnesium Chelatase ◽  
Chlorophyll Contents ◽  
Delayed Flowering ◽  
Mapping Populations ◽  
Expression Polymorphism

We previously demonstrated that maize (Zea mays) locus very oil yellow1 (vey1) encodes a putative cis-regulatory expression polymorphism at the magnesium chelatase subunit I gene (aka oil yellow1) that strongly modifies the chlorophyll content of the semi-dominant Oy1-N1989 mutants. The vey1 allele of Mo17 inbred line reduces chlorophyll content in the mutants leading to reduced photosynthetic output. Oy1-N1989 mutants in B73 reached reproductive maturity four days later than wild-type siblings. Enhancement of Oy1-N1989 by the Mo17 allele at the vey1 QTL delayed maturity further, resulting in detection of a flowering time QTL in two bi-parental mapping populations crossed to Oy1-N1989. The near isogenic lines of B73 harboring the vey1 allele from Mo17 delayed flowering of Oy1-N1989 mutants by twelve days. Just as previously observed for chlorophyll content, vey1 had no effect on reproductive maturity in the absence of the Oy1-N1989 allele. Loss of chlorophyll biosynthesis in Oy1-N1989 mutants and enhancement by vey1 reduced CO2 assimilation. We attempted to separate the effects of photosynthesis on the induction of flowering from a possible impact of chlorophyll metabolites and retrograde signaling by manually reducing leaf area. Removal of leaves, independent of the Oy1-N1989 mutant, delayed flowering but surprisingly reduced chlorophyll contents of emerging leaves. Thus, defoliation did not completely separate the identity of the signal(s) that regulates flowering time from changes in chlorophyll content in the foliage. These findings illustrate the necessity to explore the linkage between metabolism and the mechanisms that connect it to flowering time regulation.

Demonstration and characterization of two co-existing conformations of an enzyme complex by n.m.r.

1980 ◽  
Vol 8 (5) ◽  
pp. 637-637 ◽  
Author(s):  
B. BIRDSALL ◽  
A. GRONENBORN ◽  
E. I. HYDE ◽  
G. C. K. ROBERTS ◽  
J. FEENEY ◽  
...  
Keyword(s):  
Enzyme Complex

scholarly journals Further Characterization of the Magnesium Chelatase in Isolated Developing Cucumber Chloroplasts

1991 ◽  
Vol 95 (4) ◽  
pp. 1189-1196 ◽  
Author(s):  
Caroline J. Walker ◽  
Jon D. Weinstein
Keyword(s):  
Magnesium Chelatase

scholarly journals Production and characterization of an enzyme complex from a new strain of Clostridium thermocellum with emphasis on its xylanase activity

2007 ◽  
Vol 38 (2) ◽  
pp. 237-242 ◽  
Author(s):  
Werner Bessa Vieira ◽  
Leonora Rios de Souza Moreira ◽  
Amadeu Monteiro Neto ◽  
Edivaldo Ximenes Ferreira Filho
Keyword(s):  
Clostridium Thermocellum ◽  
Xylanase Activity ◽  
Enzyme Complex

scholarly journals Characterization of thermostable aminoacylase from Geobacillus sp. strain SZN

2019 ◽  
pp. 1-9
Author(s):  
Suzana Adenan ◽  
Chee Fah Wong ◽  
Haniza Hanim Mohd Zain ◽  
Saripah Salbiah Syed Abdul Azziz ◽  
Raja Noor Zaliha Raja Abd. Rahman
Keyword(s):  
Amino Acids ◽  
High Temperatures ◽  
Metal Binding ◽  
Helical Structure ◽  
Thermostable Enzyme ◽  
Point Of View ◽  
Divalent Metal Ions ◽  
Α Helix ◽  
Triton X

Aminoacylase (EC 3.5.1.14) hydrolyzes N–acetylated amino acids to produce amino acids. Although thermostable aminoacylase has been commercially produced since 2004, there was a knowledge gap in the field of understanding aminoacylase thermostability from a structural point of view. This study investigated the physical and structural properties of the purified thermostable aminoacylase SZN. The spectropolarimetry data for structural determination has indicated a gradual decrease of α-helix from 36 to 27.6%, followed by tremendous disorientation of the structure at the transition of temperatures from 60 to 70°C (27.6 to 19.5%). In contrast, the percentage of β-sheet has increased steadily over the tested temperatures. The α-helix, where notable metal binding and catalytic residues are located, was totally weakened at temperatures above 70C, thus resulted in loss of activity. The loss of the α-helical structure could further explain drastic deterioration of activity at temperatures beyond 70C. The activity of aminoacylase SZN was enhanced by divalent metal ions, such as Mn2+ and Cu2+, and inhibited by detergent Triton-X-100. As a conclusion, the isolated aminoacylase SZN was characterized as a thermostable enzyme based on the α-helical structure integrity and functional stability in high temperatures. This enzyme could be used as an alternative enzyme for bioindustries in view of its activity enhancement in high temperatures and stability in various tested inhibitors.

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