scholarly journals A point mutation, betaGln259Leu, relieves MgADP inhibition in Bacillus PS3 ATP synthase

2012 ◽  
Vol 1817 ◽  
pp. S13 ◽  
Author(s):  
Boris A. Feniouk ◽  
Chiaki Wakabayashi ◽  
Toshiharu Suzuki ◽  
Masasuke Yoshida
Keyword(s):  
Point Mutation ◽  
Atp Synthase

scholarly journals A Specific Single Nucleotide Polymorphism in the ATP Synthase Gene Significantly Improves Environmental Stress Tolerance ofSynechococcus elongatusPCC 7942

2018 ◽  
Vol 84 (18) ◽  
Author(s):  
Wenjing Lou ◽  
Xiaoming Tan ◽  
Kuo Song ◽  
Shanshan Zhang ◽  
Guodong Luan ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Stress Tolerance ◽  
Point Mutation ◽  
Atp Synthase ◽  
Point Mutations ◽  
Content Type ◽  
Protein Levels ◽  
Intracellular Atp ◽  
Stress Acclimation ◽  
Pcc 7942

ABSTRACTIn response to a broad range of habitats and environmental stresses, cyanobacteria have evolved various effective acclimation strategies, which will be helpful for improving the stress tolerances of photosynthetic organisms, including higher plants.Synechococcus elongatusUTEX 2973 and PCC 7942 possess genomes that are 99.8% identical but exhibit significant differences in cell growth and stress tolerance. In this study, we found that a single amino acid substitution at FoF1ATP synthase subunit α (AtpA), C252Y, is the primary contributor to the improved stress tolerance ofS. elongatusUTEX 2973. Site-saturation mutagenesis experiments showed that point mutations of cysteine 252 to any of the four conjugated amino acids could significantly improve the stress tolerance ofS. elongatusPCC 7942. We further confirmed that the C252Y mutation increases AtpA protein levels, intracellular ATP synthase activity, intracellular ATP abundance, transcription ofpsbAgenes (especiallypsbA2), photosystem II activity, and glycogen accumulation inS. elongatusPCC 7942. This work highlights the importance of AtpA in improving the stress tolerance of cyanobacteria and provides insight into how cyanobacteria evolve via point mutations in the face of environmental selection pressures.IMPORTANCETwo closely relatedSynechococcusstrains showed significantly different tolerances to high light and high temperature but limited genomic differences, providing us opportunities to identify key genes responsible for stress acclimation by a gene complementation approach. In this study, we confirmed that a single point mutation in the α subunit of FoF1ATP synthase (AtpA) contributes mainly to the improved stress tolerance ofSynechococcus elongatusUTEX 2973. The point mutation of AtpA, the important ATP-generating complex of photosynthesis, increases AtpA protein levels, intracellular ATP synthase activity, and ATP concentrations under heat stress, as well as photosystem II activity. This work proves the importance of ATP synthase in cyanobacterial stress acclimation and provides a good target for future improvement of cyanobacterial stress tolerance by metabolic engineering.

Paris I Dysfibrinogenemia: A Point Mutation in Intron 8 Results in Insertion of a 15 Amino Acid Sequence in the Fibrinogen γ-Chain

1993 ◽  
Vol 69 (03) ◽  
pp. 217-220 ◽  
Author(s):  
Jonathan B Rosenberg ◽  
Peter J Newman ◽  
Michael W Mosesson ◽  
Marie-Claude Guillin ◽  
David L Amrani
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Point Mutation ◽  
Genomic Dna ◽  
Comparative Sequence Analysis ◽  
Chain Gene ◽  
Molecular Defect ◽  
Nucleotide Position ◽  
Normal Individuals ◽  
Polymerase Chain

SummaryParis I dysfibrinogenemia results in the production of a fibrinogen molecule containing a functionally abnormal γ-chain. We determined the basis of the molecular defect using polymerase chain reaction (PCR) to amplify the γ-chain region of the Paris I subject’s genomic DNA. Comparative sequence analysis of cloned PCR segments of normal and Paris I genomic DNA revealed only an A→G point mutation occurring at nucleotide position 6588 within intron 8 of the Paris I γ-chain gene. We examined six normal individuals and found only normal sequence in this region, indicating that this change is not likely to represent a normal polymorphism. This nucleotide change leads to a 45 bp fragment being inserted between exons 8 and 9 in the mature γparis I chain mRNA, and encodes a 15 amino acid insert after γ350 [M-C-G-E-A-L-P-M-L-K-D-P-C-Y]. Alternative splicing of this region from intron 8 into the mature Paris I γ-chain mRNA also results after translation into a substitution of S for G at position γ351. Biochemical studies of 14C-iodoacetamide incorporation into disulfide-reduced Paris I and normal fibrinogen corroborated the molecular biologic predictions that two additional cysteine residues exist within the γpariS I chain. We conclude that the insertion of this amino acid sequence leads to a conformationallyaltered, and dysfunctional γ-chain in Paris I fibrinogen.

Skeletal and bone material phenotype in recessive osteogenesis imperfecta due to a novel homozygous point mutation in TMEM38B

2015 ◽  
Author(s):  
Emma Webb ◽  
Meena Balasubramanian ◽  
Trevor Cole ◽  
Sue Stewart ◽  
Nicola Crabtree ◽  
...  
Keyword(s):  
Osteogenesis Imperfecta ◽  
Point Mutation ◽  
Bone Material
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