An autonomous folding unit mediates the assembly of two-stranded coiled coils

Kammerer, Richard A.; Schulthess, Therese; Landwehr, Ruth; Lustig, Ariel; Engel, Jürgen; Aebi, Ueli; Steinmetz, Michel O.

doi:10.1073/pnas.95.23.13419

Cited by 171 publications

(193 citation statements)

References 40 publications

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“…Characterization of small peptides and larger recombinant regions demonstrates that trigger sequences possess the ability to form α-helices, and these helices, once formed, are hypothesized to lead to the zipping up of the entire coiled-coil (41). Although the name implies that these regions trigger coiled-coil formation, the order of assembly within IFs has not been demonstrated (39,41). An examination of IF sequences for trigger sequences has resulted in the identification of two regions with sequence similarity and, more importantly, functional requirements for coiled-coil formation.…”

Section: Discussionmentioning

confidence: 99%

“…These locations flank the early assembling region we have identified within linker 2. Assuming a conservation of structural elements between type I and II keratins and type III vimentin, the action of linker 2 as an early assembly facilitator could easily be incorporated into the model by Kammerer as an interaction that brings two polypeptide chains together and, thus, facilitates the transition from two autonomous helical folding units to a parallel in-register alignment of two monomers (step i to ii of the model of Kammerer et al (41).…”

Section: Discussionmentioning

confidence: 99%

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Characterization of the Linker 2 Region in Human Vimentin Using Site-Directed Spin Labeling and Electron Paramagnetic Resonance

et al. 2006

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Site-directed spin labeling and electron paramagnetic resonance were used to probe residues 281-304 of human vimentin, a region that has been predicted to be a non-α-helical linker and the beginning of coiled-coil domain 2B. Though no direct test of linker structure has ever been made, this region has been hypothesized to be flexible with the polypeptide chains looping away from one another. EPR analysis of spin-labeled mutants indicates that (a) several residues reside in close proximity, suggesting that adjacent linker regions in a dimer run in parallel, and that (b) the polypeptide backbone is relatively rigid and inflexible in this region. However, this region does not show the characteristics of a coiled-coil as has been identified elsewhere in the molecule. Within this region, spectra from positions 283 and 291 are unique from all others thus far examined. These positions, predicted to be in a noncoiled-coil structure, display a significantly stronger interaction than the a-d contact positions of coiled-coil regions. Analysis of the early stages of assembly by dialysis from 8 M urea and progressive thermal denaturation shows the close apposition and structural rigidity at residues 283 and 291 occurs very early in assembly and with a relatively sudden onset, well before coiled-coil formation in other parts of the molecule. These features are inconsistent with hypotheses that envision the linkers as flexible regions, or as looping away from one another, and raise the possibility that the linker may be the site at which dimer alignment and/or formation is initiated. Spin labels placed further downstream yield spectra suggesting that the first regular heptad of rod domain 2 begins at position 302. In conjunction with our previous characterization of region 305-336 and the solved structure of rod 2B from 328-405, the full extent of coiled-coil domain in rod 2B is now known, spanning from vimentin positions 302-405.Intermediate filaments (IFs 1 ) are one of the three major classes of cytoskeletal structures in metazoan cells. Though more than 60 IF genes have been defined in the human genome, most IFs are assembled from just 1 or 2 IF proteins. Which specific IF protein(s) is/are expressed varies by cell type and the state of development/differentiation (1-4).

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Characterization of the Linker 2 Region in Human Vimentin Using Site-Directed Spin Labeling and Electron Paramagnetic Resonance

et al. 2006

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“…Collision of short helical-like stretches has been suggested as a mechanism for the folding pathways of GCN4p1 (46,47). As a local factor, Gazit (35) has suggested that aromatic residues can provide two key elements for the formation of such structures: (i) an energetic contribution stemming from the -stacking itself; and (ii) specific directionality and orientation provided by the specific pattern of stacking.…”

Section: Discussionmentioning

confidence: 99%

Modulating Calcitonin Fibrillogenesis

Andreotti

Motta

2004

Journal of Biological Chemistry

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We have investigated the prefibrillar state of salmon (s) and human (h) calcitonin (CT). Size exclusion chromatography at pH 3.3 and 7.4 indicates that sCT is present in solution as a dimer, whereas hCT elutes as a monomer at pH 3.3 and as monomer-dimer at pH 7.4. Guanidine hydrochloride unfolding experiments show that dimerization is stabilized by hydrophobic interactions. We investigated the dimeric structure by multidimensional nuclear magnetic resonance spectroscopy and calculations by using an sCT mutant (LAsCT) in which Pro 23 and Arg 24 were substituted for Leu 23 and Ala 24 . As indicated by the Leu 9 -Tyr 27 and Leu 12 -Leu 19 contacts, the mutated hormone forms a head-to-tail dimer whose basic unit is an ␣-helix in the region Leu 12 -Tyr 22 . The solution behavior of LAsCT is identical to that of sCT, so the dimeric structure can safely be extended to sCT: we believe that such a structure inhibits fibril maturation in sCT. No stable dimer was observed for hCT, which we attributed to the absence of a defined helical structure. However, we suggest that intermolecular collisions of short ordered regions (for example, a sequence of turns) in hCT favors intermolecular contacts, and specific orientation can be obtained through hydrogen bond formation involving Tyr 12 , Phe 16 , and Phe 19 , with the aromatic ring acting as an acceptor. Taken together, our results indicate that hCT fibrillation can be reduced by favoring a helical dimer, obtainable by replacing the three aromatic amino acids with leucines.

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“…Because the presence of such an inducer can propagate coiled-coil formation over long distances (10), and because regulation in smooth-muscle myosin II requires the presence of at least 15 heptads (4), the chimeric S2N51 construct may not reveal important structural and functional features of S2. To gain further insight into the S2 region, and because of its clinical importance, we have determined crystal structures of the native N-terminal 126 residues of S2 from human cardiac ␤-myosin II (S2-⌬, P838-K963, covering Ϸ30% of the complete S2 subfragment) and its FHC-associated mutant E924K to 2.7-and 2.5-Å resolution, respectively.…”

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confidence: 99%

Crystal structures of human cardiac β-myosin II S2-Δ provide insight into the functional role of the S2 subfragment

Blankenfeldt

Thomä

Wray

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

101

132

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Myosin II is the major component of the muscle thick filament. It consists of two N-terminal S1 subfragments (''heads'') connected to a long dimeric coiled-coil rod. The rod is in itself twofold symmetric, but in the filament, the two heads point away from the filament surface and are therefore not equivalent. This breaking of symmetry requires the initial section of the rod, subfragment 2 (S2), to be relatively flexible. S2 is an important functional element, involved in various mechanisms by which the activity of smooth and striated muscle is regulated. We have determined crystal structures of the 126 N-terminal residues of S2 from human cardiac ␤-myosin II (S2-⌬), of both WT and the disease-associated E924K mutant. S2-⌬ is a straight parallel dimeric coiled coil, but the N terminus of one chain is disordered in WT-S2-⌬ due to crystal contacts, indicative of unstable local structure. Bulky noncanonical side chains pack into a͞d positions of S2-⌬'s N terminus, leading to defined local asymmetry and axial stagger, which could induce nonequivalence of the S1 subfragments. Additionally, S2 possesses a conserved charge distribution with three prominent rings of negative potential within S2-⌬, the first of which may provide a binding interface for the ''blocked head'' of smooth muscle myosin in the OFF state. The observation that many disease-associated mutations affect the second negatively charged ring further suggests that charge interactions play an important role in regulation of cardiac muscle activity through myosin-binding protein C.coiled coil ͉ muscle ͉ crystallography ͉ regulation ͉ familial hypertrophic cardiomyopathy M uscle contraction results from the ATP-dependent cyclic interaction of the proteins myosin II and actin, assembled in thick and thin filaments, respectively. Myosin II consists of two heavy chains, each of which binds one essential and one regulatory light chain (Fig.

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An autonomous folding unit mediates the assembly of two-stranded coiled coils

Cited by 171 publications

References 40 publications

Characterization of the Linker 2 Region in Human Vimentin Using Site-Directed Spin Labeling and Electron Paramagnetic Resonance

Characterization of the Linker 2 Region in Human Vimentin Using Site-Directed Spin Labeling and Electron Paramagnetic Resonance

Modulating Calcitonin Fibrillogenesis

Crystal structures of human cardiac β-myosin II S2-Δ provide insight into the functional role of the S2 subfragment

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