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Topic: RUBISCO

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Calvin cycle

Photosynthesis

Enzyme

NADP

Venus Flytrap

Robert Hill (British biophysicist)

Transmembrane ATPase

Citric acid cycle

ATP synthase

Glycolysis

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Oxidative phosphorylation

	Rubisco
		Rubisco, a critical element in the process of photosynthesis, is short for "ribulose-1,5-biphosphate carboxylase/oxygenase”.
		Rubisco is probably the most abundant protein in leaves, and may be the most abundant on Earth.
		Genetic engineers are trying to maximize the expression of the genes for Rubisco by moving them to different organisms, doubling the number of genes with Rubisco coding, and altering them to increase selectivity for high carbon dioxide removal.
	www.iscid.org /encyclopedia/Rubisco (235 words)

	Photosynthetic carbon reduction
		Rubisco is an exceedingly complex enzyme and the mechanism and regulation of rubisco has been studied at length.
		Thus when rubisco limits photosynthesis (i.e., the capacity to regenerate RuBP is in excess of what can be used by rubisco), photosynthesis takes on characteristics of rubisco including a strong sensitivity to CO and low sensitivity to temperature.
		In low light-grown tobacco plants, the control coefficient for rubisco was essentially zero until one half of the rubisco was lost, then the control coefficient was nearly one as rubisco was reduced further.
	www.wisc.edu /biotron/Sharkey/Courses/Biochem621/CHAPTER.html (6981 words)

	Rubisco Experiment
		Rubisco, or ribulose 1,5-bisphosphate carboxylase, is thought to be the most prolific protein on the face of the earth.
		A chicken antibody was used to bind to the rubisco proteins on the membrane, followed by a rabbit anti-chicken antibody which was linked to the enzyme horse radish peroxidase, and enzyme which gives off light.
		With these antibodies stacked onto the Rubisco proteins, the membrane was put into the Biorad camera to measure the amount of light given off by the horse radish peroxidase.
	csmres.jmu.edu /biology/Bio480/Fall05/Monday6/allrube.html (2019 words)

	Yet Another "I Love Rubisco!" Page (Site not responding. Last check: 2007-10-13)
		Rubisco is an enzyme found in green plants, and is the most abundant protein in the world.
		Rubisco is essential in the process of photosynthesis, because it catalyzes the first step in the Calvin Cycle, or dark reactions.
		Despite its usefulness to plants, Rubisco is not perfect, because it is responsible for the apparantly wasteful process of photorespiration.
	web.ics.purdue.edu /~jknoll2/Rubisco.html (223 words)

	CELL BIOLOGY 220 JMU
		Rubisco has some quite interesting features worth noting.
		Rubisco is located in the stroma of chloroplasts and consists of 16 subunits - 8 large ones and 8 small ones.
		In higher plants the large subunit (blue in the left image) is encoded by the chloroplast genome while the small subunit (green in the left image) is encoded in the nucleus.
	csm.jmu.edu /biology/courses/bio220/rubisco.html (278 words)

	Protein Spotlight Issue 38: The Plant Kingdom's sloth
		Rubisco is the key enzyme which — in the process of photosynthesis — swallows up atmospheric carbon dioxide and deals with it in such a way that oxygen is released into the air.
		Rubisco has no particular feelings for humans; it just uses the carbon from the carbon dioxide, which it recycles as sugars for its own selfish purposes.
		Rubisco is certainly easier to say, yet it is the tongue-twister 3-phospho-D-glycerate carboxylase which gives us a better idea of what Rubisco actually does.
	www.expasy.org /spotlight/back_issues/sptlt038.shtml (1411 words)

	RuBisCO - Wikipedia, the free encyclopedia
		Spacefilling view of RuBisCO showing the arrangement of the large chain dimers (white/grey) and the small chains (blue and orange).
		Ribulose-1,5-bisphosphate carboxylase/oxygenase, most commonly known by the shorter name RuBisCO, is an enzyme (EC 4.1.1.39) that is used in the Calvin cycle to catalyze the first major step of carbon fixation, a process by which the atoms of atmospheric carbon dioxide are made available to organisms in the form of energy-rich molecules such as sucrose.
		RuBisCO has a high optimal pH (can be >9.0, depending on the magnesium ion concentration) and thus becomes "activated" by the addition of carbon dioxide and magnesium to the active sites as described above.
	en.wikipedia.org /wiki/RuBisCO (2487 words)

	Archie R. Portis
		Alteration of the adenine nucleotide response and increased Rubisco activation activity of Arabidopsis Rubisco activase by site-directed mutagenesis.
		Also, Rubisco is not able to prevent oxygen from reacting with the ribulose bisphosphate during the reaction, allowing oxgenation to occur instead of carboxylation which further reduces photosynthetic potential.
		Major areas of current investigation are the role of thylakoids and light in regulation of Rubisco activase, studies of the interaction between Rubisco and Rubisco activase using site-directed mutagenesis, and a more detailed investigation of the effects of moderate heat stress on plants that appears to inhibit photosynthesis by reducing the activation of Rubisco.
	www.cropsci.uiuc.edu /faculty/portis (983 words)

	Crystal Structure of Carboxylase Reaction-oriented Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase from a Thermophilic ...
		For the activation of Rubisco, the reaction of CO with
		Sequence alignment of the Rubiscos and secondary structure of Galdieria Rubisco.
		Since N-terminal residues of the large subunit in Galdieria Rubisco are disordered and quite different from the structure of spinach enzyme's structures, large subunit sequences of N-terminal residues 1-13 were not aligned.
	www.jbc.org /cgi/content/full/274/22/15655 (4630 words)

	C4 plants
		Rubisco is an inefficient enzyme because oxygen can substitute for CO in the active site.
		What evolved was not a more efficient Rubisco, but rather a way to keep the CO concentration around the enzyme higher than the oxygen.....
		Rubisco is a large quaternary "structured" enzyme and it must have been difficult for evolution to make the correct mutation(s) to solve this problem.
	homepage.smc.edu /hodson_kent/Energetics/C4.htm (580 words)

	Dual Role of Cysteine 172 in Redox Regulation of Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase Activity and ...
		RuBisCO, incubated in 50 mM HEPES buffer (pH 7.0 to 8.0) in
		RuBisCO was activated and assayed as described in the legend to Fig.
		Activated RuBisCO from the wild type (WT) and C172A (upper left gels) or from the wild type and C192A (upper right gels) was either oxidized with DTNB or reduced with DTT as described in the legend to Fig.
	jb.asm.org /cgi/content/full/185/5/1509 (5200 words)

	THE “DARK” REACTIONS”
		The substrate for PEPC (i.e PEP) is regenerated.
		by PEPC (in the mesophyll cytoplasm) from the decarboxylase and subsequent refixation by Rubisco (in the bundlesheath cells).
		Rubisco and the PCR cycle are ONLY in bundlesheath cell chloroplasts NOT in mesophyll cell chloroplasts.
	www.clas.ufl.edu /users/gbowes/bot3503/psdkrx.html (1475 words)

	References - rubisco - HORT640 - Metabolic Plant Physiology - Department of Horticulture and Landscape Architecture - ...
		Curatti L, Giarrocco L, Salerno GL 2006 Sucrose synthase and RuBisCo expression is similarly regulated by the nitrogen source in the nitrogen-fixing cyanobacterium Anabaena sp.
		Kallis RP, Ewy RG, Portis AR Jr 2000 Alteration of the adenine nucleotide response and increased Rubisco activation activity of Arabidopsis Rubisco activase by site-directed mutagenesis.
		Pollock SV, Colombo SL, Prout DL Jr, Godfrey AC, Moroney JV 2003 Rubisco activase is required for optimal photosynthesis in the green alga Chlamydomonas reinhardtii in a low-CO(2) atmosphere.
	www.hort.purdue.edu /rhodcv/hort640c/referen/rubisco.htm (9235 words)

	From the Cover: Activation of Rubisco regulates photosynthesis at high temperature and CO2 -- Jensen 97 (24): 12937 -- ...
		The enzyme Rubisco, short for ribulose-1,5-bisphosphate carboxylase/oxygenase, is the enzyme that incorporates CO into plants
		Crafts-Brandner and Salvucci (6) show that an accelerated rate of Rubisco deactivation occurs at high temperature (steps 2 and 3), which is not matched by a faster rate of activation by activase.
		of Rubisco is known from several plant sources (9).
	www.pnas.org /cgi/content/full/97/24/12937 (1040 words)

	Alteration of the Adenine Nucleotide Response and Increased Rubisco Activation Activity of Arabidopsis Rubisco Activase ...
		Rubisco activity in the absence of ADP was measured by a two-step radiometric assay.
		The ATPase activity of recombinant Rubisco activase in the absence of ADP was measured by a spectrophotometric assay modified
		Robinson SP, Portis AR Jr (1988) Release of the nocturnal inhibitor, carboxyarabinitol-1-phosphate from ribulose bisphosphate carboxylase/oxygenase by Rubisco activase.
	www.plantphysiol.org /cgi/content/full/123/3/1077 (6054 words)

	Robert L. Houtz
		We previously proposed that an analysis of the functional significance of trimethyllysine in the LS of Rubisco may result in a significant contribution to the understanding of processes critical to functional aspects of Rubisco which are as yet unknown.
		However, methylation of Lys-14 by Rubisco LSMT does result in complete protection against proteolytic attack by trypsin and Lys-C endoprotease, a fact dramatically evident in studies comparing the loss in catalytic activity between methylated and non-methylated spinach Rubisco during limited proteolysis.
		For example, recent studies with a synthetic polypeptide version of the LS of Rubisco from acetyl-Pro-3 to Tyr-25 demonstrated that the peptide bond between Lys-14 and Ala-15 was particularly sensitive to proteolytic cleavage during incubation with pea chloropolast lysates.
	www.uky.edu /Ag/HLA/houtz/houtz.htm (1086 words)

	3D Biochem Weblog - A 3D Molecular Modeling Weblog for Teachers and Students » Rubisco
		) Rubisco is the most abundant enzyme on Earth, being about 60% of soluble leaf protein.
		, Rubisco is one of the slowest enzymes known and regulates the rate limiting step in the photosynthetic assimilation of carbon.
		Rubisco from higher plants and most photosynthetic microorganisms consists of eight large L chains (56 kd) and eight small S chains (14 kd) giving an L
	3dbiochemblog.com /?p=18 (214 words)

	Distribution of RuBisCO Genotypes along a Redox Gradient in Mono Lake, California -- Giri et al. 70 (6): 3443 -- ...
		Distribution of RuBisCO Genotypes along a Redox Gradient in Mono Lake, California -- Giri et al.
		The chlorophyll profile was constructed from a low-resolution cast made on 17 July 2000 and a high-resolution cast to define the chlorophyll maximum taken on 20 July 2000.
		Purification of the L2 RuBisCO from a marine obligately autotrophic hydrogen-oxidizing bacterium Hydrogenovibrio marinus strain MH-110.
	aem.asm.org /cgi/content/full/70/6/3443 (3114 words)

	Directed Mutation of the Rubisco Large Subunit of Tobacco Influences Photorespiration and Growth -- Whitney et al. 121 ...
		Rubisco was purified from leaf extracts by precipitation with PEG followed by ultracentrifugation through Suc density gradients.
		Rubisco kinetic parameters can only be estimated from gas-exchange measurements with plants whose Rubisco activities are low enough to limit photosynthesis under all measurement conditions.
		At high CO, the potential Rubisco activity in wild-type plants substantially exceeds the rate of electron transport and CO assimilation becomes limited by electron transport.
	www.plantphysiol.org /cgi/content/full/121/2/579 (5230 words)

	Photosynthesis - The Dark Reactions (Site not responding. Last check: 2007-10-13)
		Rubisco accounts for 16% of the protein content of the chloroplast and is likely the most abundant protein on Earth.
		In fact, we will discover in the next section that Rubisco is, in fact, very inefficient, and that a mechanism has evolved to deal with this handicap.
		The energy required for the Calvin Cycle, in the form of ATP and NADPH, comes from the light reactions.
	web.mit.edu /esgbio/www/ps/dark.html (485 words)

	The Gene for the Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase (Rubisco) Small Subunit Relocated to the Plastid ...
		The content of His-tagged small subunits was measured by densitometry of the immunoblots by comparison with a series of standards containing 0.25 to 1.2 pmol of His-tagged small subunits separated on the same gel.
		These standards were derived by separating His-tagged Rubisco holoenzyme from the purified Rubisco preparation from the tpSSuH transformant by using Ni-NTA agarose, as described in Methods.
		Because the SSuH bands in these lanes were too faint for accurate measurement, they were measured in the His-tagged Rubisco lanes, in which a lower background allowed a 10-fold greater amplification of the intensities of the labeled bands.
	www.plantcell.org /cgi/content/full/13/1/193 (7678 words)

	Leaf Interactions
		RUBISCO takes carbon dioxide from the atmosphere and attaches it to a short sugar chain with five carbon atoms.
		Where a is the fractionation due to diffusion and b is the fractionation due to the combined effects of RUBISCO and PEPC on enzymatic effects.
		Because the concentration of carbon dioxide in bundle sheath cells is made very high, and the concentration of oxygen is low, photorespiration is minimized.
	www.biology.duke.edu /bio265/sga/leaf.html (1402 words)

	Manipulation of Rubisco: the amount, activity, function and regulation -- Parry et al. 54 (386): 1321 -- Journal of ...
		Rubiscos for which assembly into the holoenzyme is less problematic.
		Rubisco activase constrains the photosynthetic potential of leaves at high temperature and CO Proceedings of the National Academy of Sciences, USA 97, 13430–13435.
		Release of the nocturnal inhibitor, carboxyarabinitol-1-phosphate, from ribulose bisphosphate carboxylase/oxygenase by Rubisco activase.
	jxb.oxfordjournals.org /cgi/content/full/54/386/1321 (7159 words)

	Plastome-encoded bacterial ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) supports photosynthesis and growth ...
		RubisCO, used for validating the procedure for measuring the carbamylation
		RubisCO (30) and is not likely to interact with the bacterial
		In view of the species specificity of RubisCO activase (30), it is unlikely that tobacco activase can regulate R.
	www.pnas.org /cgi/content/full/98/25/14738 (4316 words)

	"Green-like" and "Red-like" RubisCO cbbL Genes in Rhodobacter azotoformans -- Uchino and Yokota 20 (5): 821 -- ...
		"Green-like" and "Red-like" RubisCO cbbL Genes in Rhodobacter azotoformans
		I RubisCO is composed of eight large subunits and eight small
		Rampant horizontal transfer and duplication of RubisCO genes in eubacteria and plastids.
	mbe.oxfordjournals.org /cgi/content/full/20/5/821 (3986 words)

	Photosynthetic Dark Reaction
		Roles of the small subunits have not been clearly defined, although there is some evidence that interactions between large and small subunits may regulate catalysis.
		In the absence of the carbamate group, RuBisCO tightly binds ribulose bisphosphate (RuBP) or another sugar phosphate at the active site as a "dead end" complex, with the closed conformation, and is inactive in catalysis.
		The activase is a large multimeric protein complex that may surround RuBP Carboxylase while inducing the conformational change to the open state.
	www.rpi.edu /dept/bcbp/molbiochem/MBWeb/mb2/part1/dark.htm (1166 words)

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