Nanosecond pulsefluorometry in polarized light of G‐actin‐ϵ‐ATP and F‐actin‐ϵ‐ADP

Mihashi, Koshin; Wahl, Philippe

doi:10.1016/0014-5793(75)80625-9

Cited by 48 publications

(21 citation statements)

References 16 publications

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“…The amount of €-ATP present was estimated by comparison of the absorbance of the supernatant of TCA-precipitated protein with known amounts of €-ATP dissolved in similar buffer. The extent of incorporation varied between 0.5 and 1 .O mole of €-ATP per mole of actin, which is similar to the results obtained by other methods (Mihashi & Wahl, 1975).…”

Section: Proteinssupporting

confidence: 88%

“…Early work utilizing etheno-nucleotides led to a controversy over whether G-and F-actin showed different fluorescent lifetimes for bound €-ATP (Mihashi & Wahl, 1975;Harvey et al, 1977). A tight correlation between the quenching of €-ATP fluorescence and polymerization of actin would link conformational changes in the cleft region of actin to an important actin function.…”

mentioning

confidence: 99%

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The accessibility of etheno‐nucleotides to collisional quenchers and the nucleotide cleft in G‐ and F‐actin

Root

Reisler

1992

Protein Science

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Recent publication of the atomic structure of G-actin (Kabsch, W., Mannherz, H.G., Suck, D., Pai, E.F., & Holmes, K.C., 1990, Nature 347, 37-44) raises questions about how the conformation of actin changes upon its polymerization. In this work, the effects of various quenchers of etheno-nucleotides bound to G-and F-actin were examined in order to assess polymerization-related changes in the nucleotide phosphate site. The Mg2+-induced polymerization of actin quenched the fluorescence of the etheno-nucleotides by approximately 20% simultaneously with the increase in light scattering by actin. A conformational change at the nucleotide binding site was also indicated by greater accessibility of F-actin than G-actin to positively, negatively, and neutrally charged collisional quenchers. The difference in accessibility between G-and F-actin was greatest for I-, indicating that the environment of the etheno group is more positively charged in the polymerized form of actin. Based on calculations of the change in electric potential of the environment of the etheno group, specific polymerization-related movements of charged residues in the atomic structure of G-actin are suggested. The binding of S-1 to €-ATP-G-actin increased the accessibility of the etheno group to I-even over that in Mg2+-polymerized actin. The quenching of the etheno group by nitromethane was, however, unaffected by the binding of S-1 to actin. Thus, the binding of S-1 induces conformational changes in the cleft region of actin that are different from those caused by Mg2+ polymerization of actin. The pH dependence of collisional quenching shows that the cleft region is more accessible to collisional quenchers at pH 7 than at higher pH and suggests that changes in the environment of the cleft might contribute to the faster polymerization rates observed at lower pH.Keywords: actin; collisional quenching; nucleotide site; polymerization; structure The recently published atomic structure of G-actin facilitates the search for specific conformational changes in the actin molecule at the atomic level. Because the X-ray crystallographic structure was solved for G-actin and not F-actin, a question of particular significance is how the conformation of G-actin changes upon its polymerization to F-actin. It is known that actin hydrolyzes ATP to ADP during polymerization

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Section: Proteinssupporting

confidence: 88%

mentioning

confidence: 99%

The accessibility of etheno‐nucleotides to collisional quenchers and the nucleotide cleft in G‐ and F‐actin

Root

Reisler

1992

Protein Science

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“…The order of magnitude of the correlation time, which characterizes the dansyl cysteine residue linked to F-actin is ten times greater than the correlation time of the G-actin monomer [ 1 ]. Still it is much smaller than the correlation times of the F-actin polymer as a whole.…”

Section: Resultsmentioning

confidence: 85%

“…In a previous pulse fluorometry study, we found that the anisotropy decay of eADP bound to F-actin was characterized by a correlation time of the order of 10 ~ts This correlation time was attributed to some macromolecular motion of F-actin [ 1 ].…”

Section: Introductionmentioning

confidence: 88%

Nanosecond pulse fluorometry in polarized light of dansyl‐L‐cysteine linked to a unique SH group of F‐actin; The influence of regulatory proteins and myosin moiety

1975

Self Cite

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“…wt 5 1 000, which is somewhat larger than the known Mr 42 300 for actin [ 1 l] . The valueOobtained here is also somewhat higher than $25 5w = 1'7.4 ns obtained in [2], and #250$w = 17.9 ns obtained in [3]. Note that both measurements were made on e-ATP-labeled G-actin, and that the values quoted here had been corrected from the values measured under the experimental conditions that the authors used.…”

Section: Rotationid Relaxation Oflabeled G-actmentioning

confidence: 38%

Nanosecond fluorescence depolarization studies on actin labeled with 1,5‐IAEDANS and dansyl chloride

Tao

1978

FEBS Letters

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Nanosecond pulsefluorometry in polarized light of G‐actin‐ϵ‐ATP and F‐actin‐ϵ‐ADP

Cited by 48 publications

References 16 publications

The accessibility of etheno‐nucleotides to collisional quenchers and the nucleotide cleft in G‐ and F‐actin

The accessibility of etheno‐nucleotides to collisional quenchers and the nucleotide cleft in G‐ and F‐actin

Nanosecond pulse fluorometry in polarized light of dansyl‐L‐cysteine linked to a unique SH group of F‐actin; The influence of regulatory proteins and myosin moiety

Nanosecond fluorescence depolarization studies on actin labeled with 1,5‐IAEDANS and dansyl chloride

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