Phytofluors: Phytochrome-Based Orange Fluorescent Protein Probes

1999 ◽  
Vol 5 (S2) ◽  
pp. 1050-1051
Author(s):  
J. Clark Lagarias ◽  
Beronda L. Montgomery ◽  
John T. Murphy ◽  
Shu-Hsing Wu
Keyword(s):  
Room Temperature ◽  
Fluorescent Protein ◽  
Protein Complexes ◽  
Quantum Yields ◽  
Color Intensity ◽  
Photosynthetic Organisms ◽  
Orange Fluorescent Protein ◽  
Pigment Protein Complexes ◽  
Covalently Linked ◽  
Light Color

Plants sense the light environment using pigment-protein complexes that discriminate light color, intensity, duration and direction. The most well-studied of these photoreceptors are the phytochromes, a family of soluble biliproteins found in plants, algae and cyanobacteria. Owing to the linear tetrapyrrole pigment phytochromobilin (PΦB) or phycocyanobilin (PCB) that is covalently linked to a large polypeptide via a thioether linkage, phytochromes perceive differences in the quality and quantity of light via their ability to photointerconvert between red (λmax660 nm) and far-red (λmax730 nm) light absorbing forms. Due to an efficient Z,E photoisomerization of the double bond between the C and D-ring pyrroles, phytochromes are nonfluorescent proteins with fluorescent quantum yields less than 10“3 at room temperature (Figure 1).Phytochrome genes have been cloned from a wide variety of photosynthetic organisms.

scholarly journals The role of LHCBM1 in non-photochemical quenching in Chlamydomonas reinhardtii

2022 ◽  
Author(s):  
Xin Liu ◽  
Wojciech J Nawrocki ◽  
Roberta Croce
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Protein Complexes ◽  
Ph Sensor ◽  
High Light ◽  
Photochemical Quenching ◽  
Knock Out ◽  
Photosynthetic Organisms ◽  
Pigment Protein Complexes ◽  
Non Photochemical Quenching

Non-photochemical quenching (NPQ) is the process that protects photosynthetic organisms from photodamage by dissipating the energy absorbed in excess as heat. In the model green alga Chlamydomonas reinhardtii, NPQ was abolished in the knock-out mutants of the pigment-protein complexes LHCSR3 and LHCBM1. However, while LHCSR3 was shown to be a pH sensor and switching to a quenched conformation at low pH, the role of LHCBM1 in NPQ has not been elucidated yet. In this work, we combine biochemical and physiological measurements to study short-term high light acclimation of npq5, the mutant lacking LHCBM1. We show that while in low light in the absence of this complex, the antenna size of PSII is smaller than in its presence, this effect is marginal in high light, implying that a reduction of the antenna is not responsible for the low NPQ. We also show that the mutant expresses LHCSR3 at the WT level in high light, indicating that the absence of this complex is also not the reason. Finally, NPQ remains low in the mutant even when the pH is artificially lowered to values that can switch LHCSR3 to the quenched conformation. It is concluded that both LHCSR3 and LHCBM1 need to be present for the induction of NPQ and that LHCBM1 is the interacting partner of LHCSR3. This interaction can either enhance the quenching capacity of LHCSR3 or connect this complex with the PSII supercomplex.

On the Correlation between Oxygen Uptake in Plastids of Greening Etiolated Oat Leaves and Pigment Photooxidation

1985 ◽  
Vol 40 (9-10) ◽  
pp. 699-704 ◽  
Author(s):  
Fabrice Franck ◽  
Georg H . Schmid
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Evolution ◽  
Room Temperature ◽  
Protein Complexes ◽  
Specific Interaction ◽  
Experimental Conditions ◽  
Etiolated Leaves ◽  
Fluorescence Transient ◽  
Pigment Protein Complexes ◽  
Absorbance Band

Abstract Changes in oxygen evolution or uptake in illuminated plastids were studied during the early stages of greening in etiolated leaves. An oxygen uptake was observed in etioplasts, which persisted even after the appearance of oxygen evolution. This oxygen uptake was most pronounced in etioplasts or in plastids prepared after redarkening the plants. Incubation of pre-illuminated etioplasts in the presence of NADPH resulted in an inhibition of the uptake in a subsequent illumination. Addition of NADPH had three further consequences: a shift of the chlorophyllide absorbance band to 682 nm, an inhibition of pigment photodestruction and the appearance of a light-induced fluorescence transient at room temperature. Inhibition of pigment photodestruction by NADPH was maximal when the experimental conditions favoured the formation of the P682 chlorophyllide-protein. It is inferred that the oxygen uptake seen under these conditions is due to pigment photooxidation. Inhibition of both phenomena by NADPH is ascribed to the specific interaction of the nucleotide with the pigment-protein complexes and to the ability of these complexes to undergo the light-induced chlorophyllide microcycle, described by Franck and Inoue (Photobiochem. Photobiophys. 8, 85-96, 1984). In the leaf, NADPH is thought to play the same role.

scholarly journals An orange fluorescent protein tagging system for real-time pollen tracking

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
J Hollis Rice ◽  
Reginald J Millwood ◽  
Richard E Mundell ◽  
Orlando D Chambers ◽  
Laura L Abercrombie ◽  
...  
Keyword(s):  
Real Time ◽  
Fluorescent Protein ◽  
Orange Fluorescent Protein ◽  
Protein Tagging ◽  
Tagging System

Carotenoidless pigment-protein complexes of the sulfur photosynthetic bacterium Ectothiorhodospira haloalkaliphila

2013 ◽  
Vol 453 (1) ◽  
pp. 304-307 ◽  
Author(s):  
A. A. Ashikhmin ◽  
Yu. E. Erokhin ◽  
Z. K. Makhneva ◽  
A. A. Moskalenko
Keyword(s):  
Protein Complexes ◽  
Photosynthetic Bacterium ◽  
Pigment Protein Complexes

scholarly journals Stoichiometry and Turnover of the Bacterial Flagellar Switch Protein FliN

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Nicolas J. Delalez ◽  
Richard M. Berry ◽  
Judith P. Armitage
Keyword(s):  
Copy Number ◽  
Motor Proteins ◽  
Fluorescent Protein ◽  
Protein Complexes ◽  
Content Type ◽  
Rotation Direction ◽  
Cell Measurement ◽  
Biological Complexes ◽  
And Function

ABSTRACTSome proteins in biological complexes exchange with pools of free proteins while the complex is functioning. Evidence is emerging that protein exchange can be part of an adaptive mechanism. The bacterial flagellar motor is one of the most complex biological machines and is an ideal model system to study protein dynamics in large multimeric complexes. Recent studies showed that the copy number of FliM in the switch complex and the fraction of FliM that exchanges vary with the direction of flagellar rotation. Here, we investigated the stoichiometry and turnover of another switch complex component, FliN, labeled with the fluorescent protein CyPet, inEscherichia coli. Our results confirm that,in vivo, FliM and FliN form a complex with stoichiometry of 1:4 and function as a unit. We estimated that wild-type motors contained 120 ± 26 FliN molecules. Motors that rotated only clockwise (CW) or counterclockwise (CCW) contained 114 ± 17 and 144 ± 26 FliN molecules, respectively. The ratio of CCW-to-CW FliN copy numbers was 1.26, very close to that of 1.29 reported previously for FliM. We also measured the exchange of FliN molecules, which had a time scale and dependence upon rotation direction similar to those of FliM, consistent with an exchange of FliM-FliN as a unit. Our work confirms the highly dynamic nature of multimeric protein complexes and indicates that, under physiological conditions, these machines might not be the stable, complete structures suggested by averaged fixed methodologies but, rather, incomplete rings that can respond and adapt to changing environments.IMPORTANCEThe flagellum is one of the most complex structures in a bacterial cell, with the core motor proteins conserved across species. Evidence is now emerging that turnover of some of these motor proteins depends on motor activity, suggesting that turnover is important for function. The switch complex transmits the chemosensory signal to the rotor, and we show, by using single-cell measurement, that both the copy number and the fraction of exchanging molecules vary with the rotational bias of the rotor. When the motor is locked in counterclockwise rotation, the copy number is similar to that determined by averaged, fixed methodologies, but when locked in a clockwise direction, the number is much lower, suggesting that that the switch complex ring is incomplete. Our results suggest that motor remodeling is an important component in tuning responses and adaptation at the motor.

scholarly journals The behaviour of visual purple at low temperature

1941 ◽  
Vol 179 (977) ◽  
pp. 151-159 ◽  
Keyword(s):  
Aqueous Solution ◽  
Low Temperature ◽  
Low Temperatures ◽  
Room Temperature ◽  
Absorption Curve ◽  
Quantum Yields

Visual purple is soluble and stable in a mixture of glycerol and water (3:1). At room temperature the spectrum of such a solution is identical with that of the aqueous solution. At — 73° C the peak of the absorption curve is higher and narrower than at room temperature, and it is shifted towards longer waves. The product of photodecomposition at — 73° C has a spectrum in ­ dependent of pH and is at low temperatures thermostable and photostable, but at room temperature it decomposes therm ally to indicator yellow. The primary product appears to be identical with transient orange. The quantum yields of the photoreaction at low and at room temperature are of the same order.

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