Small- and large-scale conformational changes of adenylate kinase: A molecular dynamics study of the subdomain motion and mechanics
Adenylate kinase, an enzyme that catalyzes the phosphoryl transfer between ATP and AMP, can interconvert between the open and catalytically potent (closed) forms even without binding ligands. Several aspects of the enzyme elasticity and internal...
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Adenylate kinase, an enzyme that catalyzes the phosphoryl transfer between ATP and AMP, can interconvert between the open and catalytically potent (closed) forms even without binding ligands. Several aspects of the enzyme elasticity and internal dynamics are analyzed here by atomistic molecular dynamics simulations covering a total time span of 100 ns. This duration is sufficiently long to reveal a partial conversion of the enzyme that proceeds through jumps between structurally different substates. The intra- and intersubstates contributions to the enzyme's structural fluctuations are analyzed and compared both in magnitude and directionality. It is found that, despite the structural heterogeneity of the visited conformers, the generalized directions accounting for conformational fluctuations within and across the substates are mutually consistent and can be described by a limited set of collective modes. The functional-oriented nature of the consensus modes is suggested by their good overlap with the deformation vector bridging the open and closed crystal structures. The consistency of adenylate kinase's internal dynamics over timescales wide enough to capture intra- and intersubstates fluctuations adds elements in favor of the recent proposal that the free (apo) enzyme possesses an innate ability to sustain the open/close conformational changes. © 2008 by the Biophysical Society.
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“An Older Light Than Ours”: Faulkner’s Reflections on Race and Racism in Light in August
This article examines William Faulkner’s reflections on race and racism in Light in August, by focusing on the crucial role that consciousness and psychology play in the novel for the construction of characters and their view of reality and of...
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This article examines William Faulkner’s reflections on race and racism in Light in August, by focusing on the crucial role that consciousness and psychology play in the novel for the construction of characters and their view of reality and of themselves. Light in August does not reproduce the South’s pervading racism as experienced by Faulkner, but undertakes a close dissection of a collective racialized imaginary. In order to support this argument, the analysis focuses on three different aspects: First, the narrative strategy of alternating subjective perspectives that explores the consensus-building dynamics, which condition perception and cognition as much as they generate prejudice and racism. Second, the community’s conception of race as an existential condition of insurmountable ontological difference appears to be intimately wedded to common concepts of gender. This conception is radicalized through a Protestant spirit of guilt and punishment as existential imperatives. Finally, the article analyzes Joe Christmas as a psychotic character by examining the process of his narrative construction and analyzing the extent to which his dubious racial identity and existential dilemma are presented as the result of racist discourse and not of “incompatibilities of blood.”
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Hybridity as a “Narrative of Liberation” in Trevor D. Rhone’s Old Story Time
“The problem is important. I propose nothing short of the liberation of the man of color from himself” (8), writes Frantz Fanon in Black Skin, White Masks. Patrick Taylor has been identifying what he calls the “narrative of liberation” throughout...
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“The problem is important. I propose nothing short of the liberation of the man of color from himself” (8), writes Frantz Fanon in Black Skin, White Masks. Patrick Taylor has been identifying what he calls the “narrative of liberation” throughout Fanon’s critical work, and his analysis of this can be linked with phenomena of hybridity. In Trevor D. Rhone’s play Old Story Time, hybridity is presented as such a liberating narrative. Hybridity is included in the play on several levels, beginning with the setting. The vernacular used by many of the play’s characters also reveals its hybrid character. Furthermore, on the formal level Trevor Rhone has created a drama that resists categorization into the Western form of epic drama by emphasizing the role of the Caribbean storytelling tradition. On the level of characters, Miss Aggy overcomes her self-destructive internalized racism in the final scene when she accepts the hybrid nature of her identity. In this sense, Old Story Time incorporates what Taylor terms an “imperative of liberation” (188). Read as an allegory to the society of the West Indies, the play calls for the acceptance of its hybrid nature as a means of overcoming the colonial legacy.
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Don DeLillo and Society’s Reorientation to Time and Space: An Interpretation of Cosmopolis
This essay reads Don DeLillo’s Cosmopolis as a novelization of social theories of time and space as expressed across various academic disciplines. Changing conceptions of time and space point to an underlying change in the social structure. I thus...
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This essay reads Don DeLillo’s Cosmopolis as a novelization of social theories of time and space as expressed across various academic disciplines. Changing conceptions of time and space point to an underlying change in the social structure. I thus view DeLillo’s novel as social theory. Economist Jeremy Rifkin recently wrote, “[t]he great turning points in human history are often triggered by changing conceptions of space and time. Sometimes, the adoption of a single technology can be transformative in nature, changing the very way our minds filter the world” (89). Eric Packer lives in a world with a multitude of adopted new technologies. His reflections on language embody this mental filtering. Cyber-capital, and digitization in general, represent these new technologies. Packer’s desire to “live on a disc” (105), epitomizes the novel’s portrayal of changing conceptions of time and space. This paper thus explores expressions of the inadequacy of contemporary language under these “turning points in human history.” It demonstrates how statements on language reflect society’s mental filtering or changing orientation to time and space. Cosmopolis could be viewed as a redescription project.
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