|
Plant Physiol, November 2001, Vol. 127, pp. 1053-1064
Exceptional Sensitivity of Rubisco Activase to Thermal
Denaturation in Vitro and in Vivo1
Michael E.
Salvucci,*
Katherine W.
Osteryoung,2
Steven
J.
Crafts-Brandner, and
Elizabeth
Vierling
Western Cotton Research Laboratory, United States Department of
Agriculture-Agricultural Research Service, 4135 East Broadway Road,
Phoenix, Arizona 85040-8803 (M.E.S., S.J.C.-B.); and Department of
Biochemistry, University of Arizona, Tucson, Arizona 85721 (K.W.O.,
E.V.)
Heat stress inhibits photosynthesis by reducing the activation of
Rubisco by Rubisco activase. To determine if loss of activase function
is caused by protein denaturation, the thermal stability of activase
was examined in vitro and in vivo and compared with the stabilities of
two other soluble chloroplast proteins. Isolated activase exhibited a
temperature optimum for ATP hydrolysis of 44°C compared with  60°C
for carboxylation by Rubisco. Light scattering showed that
unfolding/aggregation occurred at 45°C and 37°C for activase in the
presence and absence of ATP S, respectively, and at 65°C for
Rubisco. Addition of chemically denatured rhodanese to heat-treated
activase trapped partially folded activase in an insoluble complex at
treatment temperatures that were similar to those that caused increased
light scattering and loss of activity. To examine thermal stability in
vivo, heat-treated tobacco (Nicotiana rustica cv
Pulmila) protoplasts and chloroplasts were lysed with detergent in the
presence of rhodanese and the amount of target protein that aggregated
was determined by immunoblotting. The results of these experiments
showed that thermal denaturation of activase in vivo occurred at
temperatures similar to those that denatured isolated activase and far
below those required to denature Rubisco or phosphoribulokinase. Edman
degradation analysis of aggregated proteins from tobacco and pea
(Pisum sativum cv "Little Marvel") chloroplasts
showed that activase was the major protein that denatured in response
to heat stress. Thus, loss of activase activity during heat stress is
caused by an exceptional sensitivity of the protein to thermal
denaturation and is responsible, in part, for deactivation of Rubisco.
1
Mention of a trademark, proprietary product, or
vendor does not constitute a guarantee or warranty of the product by
the U.S. Department of Agriculture and does not imply its approval to
the exclusion of other products or vendors that may also be suitable.
2
Present address: Department of Plant Biology, Michigan
State University, East Lansing, MI 48824-1312.
*
Corresponding author; e-mail msalvucci{at}wcrl.ars.usda.gov; fax
602-437-1274.
© 2001 American Society of Plant Physiologists
This article has been cited by other articles:
|
|
|
|
 
M. E. Salvucci
Association of Rubisco activase with chaperonin-60{beta}: a possible mechanism for protecting photosynthesis during heat stress
J. Exp. Bot.,
May 1, 2008;
59(7):
1923 - 1933.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. F. Sage, D. A. Way, and D. S. Kubien
Rubisco, Rubisco activase, and global climate change
J. Exp. Bot.,
May 1, 2008;
59(7):
1581 - 1595.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
I. Kurek, T. K. Chang, S. M. Bertain, A. Madrigal, L. Liu, M. W. Lassner, and G. Zhu
Enhanced Thermostability of Arabidopsis Rubisco Activase Improves Photosynthesis and Growth Rates under Moderate Heat Stress
PLANT CELL,
October 1, 2007;
19(10):
3230 - 3241.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. J. Weston, W. L. Bauerle, G. A. Swire-Clark, B. d. Moore, and Wm. V. Baird
Characterization of Rubisco activase from thermally contrasting genotypes of Acer rubrum (Aceraceae)
Am. J. Botany,
June 1, 2007;
94(6):
926 - 934.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
O. Stasik and H. G. Jones
Response of photosynthetic apparatus to moderate high temperature in contrasting wheat cultivars at different oxygen concentrations
J. Exp. Bot.,
June 1, 2007;
58(8):
2133 - 2143.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. E. Salvucci, B. P. DeRidder, and A. R. Portis Jr
Effect of activase level and isoform on the thermotolerance of photosynthesis in Arabidopsis
J. Exp. Bot.,
November 1, 2006;
57(14):
3793 - 3799.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Y.-P. Cen and R. F. Sage
The Regulation of Rubisco Activity in Response to Variation in Temperature and Atmospheric CO2 Partial Pressure in Sweet Potato
Plant Physiology,
October 1, 2005;
139(2):
979 - 990.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Kim and A. R. Portis Jr
Temperature Dependence of Photosynthesis in Arabidopsis Plants with Modifications in Rubisco Activase and Membrane Fluidity
Plant Cell Physiol.,
March 1, 2005;
46(3):
522 - 530.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. E. Salvucci and S. J. Crafts-Brandner
Relationship between the Heat Tolerance of Photosynthesis and the Thermal Stability of Rubisco Activase in Plants from Contrasting Thermal Environments
Plant Physiology,
April 1, 2004;
134(4):
1460 - 1470.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. J. Crafts-Brandner and M. E. Salvucci
Sensitivity of Photosynthesis in a C4 Plant, Maize, to Heat Stress
Plant Physiology,
August 1, 2002;
129(4):
1773 - 1780.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
