scholarly journals Crystallisation of Wild-Type and Variant Forms of a Recombinant Plant Enzyme β-D-Glucan Glucohydrolase from Barley (Hordeum vulgare L.) and Preliminary X-ray Analysis

2010 ◽  
Vol 11 (7) ◽  
pp. 2759-2769 ◽  
Author(s):  
Sukanya Luang ◽  
James R. Ketudat Cairns ◽  
Victor A. Streltsov ◽  
Maria Hrmova
2020 ◽  
Vol 21 (4) ◽  
pp. 1546 ◽  
Author(s):  
Olga A. Andrzejczak ◽  
Jesper F. Havelund ◽  
Wei-Qing Wang ◽  
Sergey Kovalchuk ◽  
Christina E. Hagensen ◽  
...  

Overexpression of phytoglobins (formerly plant hemoglobins) increases the survival rate of plant tissues under hypoxia stress by the following two known mechanisms: (1) scavenging of nitric oxide (NO) in the phytoglobin/NO cycle and (2) mimicking ethylene priming to hypoxia when NO scavenging activates transcription factors that are regulated by levels of NO and O2 in the N-end rule pathway. To map the cellular and metabolic effects of hypoxia in barley (Hordeum vulgare L., cv. Golden Promise), with or without priming to hypoxia, we studied the proteome and metabolome of wild type (WT) and hemoglobin overexpressing (HO) plants in normoxia and after 24 h hypoxia (WT24, HO24). The WT plants were more susceptible to hypoxia than HO plants. The chlorophyll a + b content was lowered by 50% and biomass by 30% in WT24 compared to WT, while HO plants were unaffected. We observed an increase in ROS production during hypoxia treatment in WT seedlings that was not observed in HO seedlings. We identified and quantified 9694 proteins out of which 1107 changed significantly in abundance. Many proteins, such as ion transporters, Ca2+-signal transduction, and proteins related to protein degradation were downregulated in HO plants during hypoxia, but not in WT plants. Changes in the levels of histones indicates that chromatin restructuring plays a role in the priming of hypoxia. We also identified and quantified 1470 metabolites, of which the abundance of >500 changed significantly. In summary the data confirm known mechanisms of hypoxia priming by ethylene priming and N-end rule activation; however, the data also indicate the existence of other mechanisms for hypoxia priming in plants.


1981 ◽  
Vol 46 (1-2) ◽  
pp. 53-64 ◽  
Author(s):  
Barbro Jende-Strid ◽  
Birger Lindberg Møller

1979 ◽  
Vol 44 (4) ◽  
pp. 235-254 ◽  
Author(s):  
Otto Machold ◽  
David J. Simpson ◽  
Birger Lindberg Møller

Hereditas ◽  
2004 ◽  
Vol 131 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Bent L. Petersen ◽  
Marianne G. Møller ◽  
Poul Erik Jensen ◽  
Knud W. Henningsen

1997 ◽  
Vol 322 (3) ◽  
pp. 815-822 ◽  
Author(s):  
Mette D. ANDERSEN ◽  
Arne JENSEN ◽  
Jon D. ROBERTUS ◽  
Robert LEAH ◽  
Karen SKRIVER

To investigate structure–function relationships in plant chitinases, we have developed a heterologous expression system for the 26 kDa endochitinase from Hordeum vulgare L. (barley). Escherichia coli cells harbouring the gene in a T7 RNA polymerase-based expression vector synthesized completely insoluble recombinant protein under standard induction conditions at 37 °C. However, a concentration of soluble recombinant protein of approx. 15 mg/l was achieved by inducing bacteria at low temperature (15 °C). Recombinant endochitinase was purified to homogeneity and shown to be structurally and functionally identical to the seed protein. An average of three disulphide bonds are present in the recombinant enzyme, consistent with the number found in the natural form. The seed and recombinant proteins showed the same specific activity towards a high-molecular-mass substrate and exhibited similar anti-fungal activity towards Tricoderma reesei. Site-directed mutagenesis was used to replace residues that are likely to be involved in the catalytic event, based on structural similarities with lysozyme and on sequence alignments with related chitinases. The Glu67 → Gln mutation resulted in a protein with undetectable activity, while the Glu89 → Gln mutation yielded an enzyme with 0.25% of wild-type specific activity. This suggests that two acidic residues are essential for catalytic activity, similar to the situation with many other glycosyl hydrolases. Examination of conserved residues stretching into the proposed substrate binding cleft suggests that Asn124 also plays an important functional role.


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