Atomic structure of the actin: DNase I complex

Kabsch, Wolfgang; Mannherz, Hans Georg; Suck, Dietrich; Pai, E.F.; Holmes, Kenneth C.

doi:10.1038/347037a0

Cited by 1,804 publications

(1,502 citation statements)

References 59 publications

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“…Thus three regions of contact of Tb4 with actin can be distinguished: the N-and C-terminal helixes and the extended region in between, which contains a widely-spread actin binding consensus sequence ( 17 LKKTET 22 ). Using the standard view of actin [Kabsch et al, 1990] Tb4 extends from the lower part to the upper part of actin thereby binding to regions that are exposed at the barbed (area between subdomains 1 and 3) and pointed-end (area between subdomains 2 and 4) of actin. By this mode of interaction Tb4 blocks both the barbed-and pointed-end of actin and thereby its ability to associate to either filament end.…”

Section: Structure Of the Actin:thymosin B4 Complexmentioning

confidence: 99%

The β‐thymosins: Intracellular and extracellular activities of a versatile actin binding protein family

Mannherz

Hannappel

2009

Cell Motil. Cytoskeleton

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109

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The b-thymosins are N-terminally acetylated peptides of about 5 kDa molecular mass and composed of about 40-44 amino acid residues. The first member of the family, thymosin b4, was initially isolated from thymosin fraction 5, prepared in five steps from calf thymus. Thymosin b4 was supposed to be specifically produced and released by the thymic gland and to possess hormonal activities modulating the immune response. Various paracrine effects have indeed been reported for these peptides such as cardiac protection, angiogenesis, stimulation of wound healing, and hair growth. Besides these paracrine effects, it was noted that b-thymosins occur in high concentration in the cytoplasm of many eukaryotic cells and bind to the cytoskeletal component actin. Subsequently it became apparent from in vitro experiments that they preferentially bind to monomeric (G-)actin and stabilize it in its monomeric form. Due to this ability the b-thymosins are the main intracellular actin sequestering factor, i.e., they posses the ability to remove monomeric actin from the dynamic assembly and disassembly processes of the actin cytoskeleton that constantly occur in activated cells. In this review we will concentrate on the intracellular activity and localization of the b-thymosins, i.e., their modulating effect on the actin cytoskeleton. Cell Motil. Cytoskeleton 66: 839-851, 2009. '

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Section: Structure Of the Actin:thymosin B4 Complexmentioning

confidence: 99%

The β‐thymosins: Intracellular and extracellular activities of a versatile actin binding protein family

Mannherz

Hannappel

2009

Cell Motil. Cytoskeleton

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109

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“…Besides appropriate pH adjusted by buffer, ions and ATP as well as the concentration of G-actin play critical roles in polymerization. Although there is no atomic model of the actin filament, a model of F-actin was made using parameters derived from the x-ray diffraction data of flow oriented F actin and the crystal structure of the actin monomer [34].…”

Section: Fig12mentioning

confidence: 99%

Fluorescence labeling and computational analysis of the strut of myosin’s 50 kDa cleft

Gawalapu¹,

Root²

2006

Archives of Biochemistry and Biophysics

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Gawalapu, Ravi Kumar. Fluorescence labeling and computational analysis of the strut of myosin's 50 kDa cleft. Doctor of Philosophy (Biochemistry), August 2007, 148 pp., 3 tables, 60 illustrations, 120 references, 120 titles.In order to understand the structural changes in myosin S1, fluorescence polarization and computational dynamics simulations were used. Dynamics simulations on the S1 motor domain indicated that significant flexibility was present throughout the molecular model. The constrained opening versus closing of the 50 kDa cleft appeared to induce opposite directions of movement in the lever arm. A sequence called the "strut" which traverses the 50 kDa cleft and may play an important role in positioning the actomyosin binding interface during actin binding is thought to be intimately linked to distant structural changes in the myosin's nucleotide cleft and neck regions. To study the dynamics of the strut region, a method of fluorescent labeling of the strut was discovered using the dye CY3. CY3 served as a hydrophobic tag for purification by hydrophobic interaction chromatography which enabled the separation of labeled and unlabeled species of S1 including a fraction labeled specifically at the strut sequence. The high specificity of labeling was verified by proteolytic digestions, gel electrophoresis, and mass spectroscopy.Analysis of the labeled S1 by collisional quenching, fluorescence polarization, and actinactivated ATPase activity were consistent with predictions from structural models of the probe's location. Although the fluorescent intensity of the CY3 was insensitive to actin binding, its fluorescence polarization was notably affected. Intriguingly, the mobility of the probe increases upon S1 binding to actin suggesting that the CY3 becomes displaced from interactions with the surface of S1 and is consistent with a structural change in the strut due to cleft motions. Labeling the strut reduced the affinity of S1 for actin but did not prevent actin-activated ATPase activity which makes it a potentially useful probe of the actomyosin interface. The different conformations of myosin S1 indicated that the strut is not as flexible as several other key regions of myosin as determined by the application of force constraints to elastic portions of the myosin

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“…Indeed, in the atomic structure of actin [2], one ~-helix occurs between residues 79 and 92 and another one between residues 338 and 348. These two or-helices are outside of subdomain-1 [2] and bear two myosin-binding sites that are effective in the presence of ATP-Mg [5,28] The second motif (a] and a2); al was constituted by sequence residues N92 to P112 comprising hydrophobic residues V96, L110 and clusters L104 and L105.…”

Section: Precise Local Analysis Of Hydrophobic Motifs 4 and B Inmentioning

confidence: 99%

“…These two or-helices are outside of subdomain-1 [2] and bear two myosin-binding sites that are effective in the presence of ATP-Mg [5,28] The second motif (a] and a2); al was constituted by sequence residues N92 to P112 comprising hydrophobic residues V96, L110 and clusters L104 and L105. a2 constituted by sequence K359-F375 comprises hydrophobic residues Y362, F375 and the cluster (1369, V370 I ig.…”

Section: Precise Local Analysis Of Hydrophobic Motifs 4 and B Inmentioning

confidence: 99%

“…Atomic resolution of the actin structure [1,2] and the threeciimensional atomic model of F-actin decorated with rabbit ~aymotryptic-S1 [3] or Dictyostelium myosin S1 [4] revealed I ~cations of the myosin head on F-actin. This molecular model f the actin-myosin complex derived from the X-ray structure l zveals a close contact between a myosin subfragment-I and 1 ~o actin monomers.…”

Section: ~ Introductionmentioning

confidence: 99%

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Two identical hydrophobic clusters are present on the same actin monomer: interaction between one myosin subfragment‐1 and two actin monomers

Labbé¹,

Boyer²,

Benyamin³

1995

FEBS Letters

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Two-dimensional hydrophobic clusters analysis (IICA) was used to compare the distribution of hydrophobic clusters along various actin sequence. HCA-deduced patterns were not altered by amino-acid variations throughout the evolution of actin and we observed similar hydrophobic motifs comprising myosin subfragment-I ATP-independent binding sites. HCA suggested the presence of two groups of identical hydrophobic motifs (A~ and A2) which bound on each side of the S1 (63 kDa-31 kDa) connecting segment in relation with two actin monomers. This connection is important in communications between actin-and nucleotide-binding sites. We postulate that some relation and message between the two motifs A~ and A 2 take place through myosin subfragment-I (63 kDa-31 kDa) connecting segment.1~ ey words'," Acto-myosin; Hydrophobic cluster; Structure comparison 1~ IntroductionIdentification of the actin-myosin interface is essential in t nderstanding the cyclical enzymatic and mechanical process c f myofibrillar contraction.Atomic resolution of the actin structure [1,2] and the threeciimensional atomic model of F-actin decorated with rabbit ~aymotryptic-S1 [3] or Dictyostelium myosin S1 [4] revealed I ~cations of the myosin head on F-actin. This molecular model f the actin-myosin complex derived from the X-ray structure l zveals a close contact between a myosin subfragment-I and 1 ~o actin monomers. A first contact includes carboxyl residues ,2, 3, 4, 24, 25, 99 and 100. In a second contact, exposed actin 1 ydrophobic residues 144, 341,345,349 and 352 are concerned. "he third contact involves proline residues (332-333) of actin. ~11 of these contacts involve a single monomer. A second mon-~,mer is close to the myosin heavy chain and the interaction i ~cludes the cz-helix formed by actin residues Trp79 to Asn92 flat formed a weak binding contact and was cross-linked [5,6].The Taylor-Amos model [7] of acto-S1 suggests that S1 has n extensive contact with an actin monomer (acl) and a weaker ,. ontact with an adjacent actin monomer (ac2); and two differ-,, nt rigor complexes were suggested [8,9], with SI binding to :-actin occurring in two steps with actin monomers. Using .,uccessively EDC and DMS, we previously cross-linked two lnonomers to 20-kDa and 50-kDa skeletal S1 fragments, re-: Corresponding author. Fax: (33) (67) 60 94 78.spectively [10], and in vitro studies showed that subfragment-I alone can produce the sliding movement of the actin filament [111.Chemical cross-linking [12], NMR [13,14] and immunochemical studies [15,16,[17][18][19][20] have pinpointed actin segments in subdomain-1, residues 1 28, 96-103, 112-125, 338 348 and 360-372 which are able to bind with the myosin head.Furthermore, the (27 kDa-50 kDa-20 kDa) trypsin split myosin subfragment-1, which could no longer be activated by actin, did not bind to the two sites located in the 96-125 region, but it still interacted with the 338-348 and 360--372 segments [191. The presence of hydrophobic interactions in the actin myosin complex have already been sugge...

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Atomic structure of the actin: DNase I complex

Cited by 1,804 publications

References 59 publications

The β‐thymosins: Intracellular and extracellular activities of a versatile actin binding protein family

The β‐thymosins: Intracellular and extracellular activities of a versatile actin binding protein family

Fluorescence labeling and computational analysis of the strut of myosin’s 50 kDa cleft

Two identical hydrophobic clusters are present on the same actin monomer: interaction between one myosin subfragment‐1 and two actin monomers

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