Interhelical Salt Bridges , Coiled - Coil Stability
نویسندگان
چکیده
absorbed in the atmosphere, the NIR water vapor bands. Thus, we see no way of defending Stephen's statement that conclusions based on broad-band measurements (1) are inconsistent with other existing data sets where discrepancies were found to occur between measurements in spectral bands and theory. Instead, the broad-band solar absorption findings presented in our report (1) are entirely consistent with existing spectral data sets, as both show cloud absorption to be greater than the magnitude predicted by theory. Stephens makes another critical error when determining cloud absorption with the use of results shown in figure 6 of our report (1). Stephens determined cloud absorption, A, from the relationship A + R + T = 1, where R is reflectance and T is transmission, and he states that figure 6 in our report (1 ) indicates that a cloud with reflectance (albedo) 0.45 would absorb 0.40. His error is in assuming A occurs entirely in cloud. He does not account for the absorbing surface or for the lower 10 km of the atmosphere as well. An appropriate relationship between R and A is R + A = 1, where A now is the fractional absorption by the combined atmosphere-surface system (7). The analysis shown in figure 6 in our report is not by itself sufficient to determine cloud absorption; again we would refer the reader to figure 2 in our report (or Fig. 1 here). Consequently, contrary to Stephens erroneous conclusion, in our report (1) figure 1 is entirely consistent with figure 6 in our report, as those figures represent alternative ways of viewing
منابع مشابه
Configurational entropy elucidates the role of salt-bridge networks in protein thermostability.
Detailed knowledge of how networks of surface salt bridges contribute to protein thermal stability is essential not only to understand protein structure and function but also to design thermostable proteins for industrial applications. Experimental studies investigating thermodynamic stability through measurements of free energy associated with mutational alterations in proteins provide only ma...
متن کاملSide-chain pairing preferences in the parallel coiled-coil dimer motif: insight on ion pairing between core and flanking sites.
A new strategy for rapid evaluation of sequence-stability relationships in the parallel coiled-coil motif is described. The experimental design relies upon thiol-thioester exchange equilibria, an approach that is particularly well suited to examination of heterodimeric systems. Our model system has been benchmarked by demonstrating that it can quantitatively reproduce previously reported trends...
متن کاملSite-specific Isopeptide Bridge Tethering of Chimeric gp41 N-terminal Heptad Repeat Helical Trimers for the Treatment of HIV-1 Infection
Peptides derived from the N-terminal heptad repeat (NHR) of HIV-1 gp41 can be potent inhibitors against viral entry when presented in a nonaggregating trimeric coiled-coil conformation via the introduction of exogenous trimerization motifs and intermolecular disulfide bonds. We recently discovered that crosslinking isopeptide bridges within the de novo helical trimers added exceptional resistan...
متن کاملInterhelical salt bridges, coiled-coil stability, and specificity of dimerization.
absorbed in the atmosphere, the NIR water vapor bands. Thus, we see no way of defending Stephen's statement that conclusions based on broad-band measurements (1) are inconsistent with other existing data sets where discrepancies were found to occur between measurements in spectral bands and theory. Instead, the broad-band solar absorption findings presented in our report (1) are entirely consis...
متن کاملDo interhelical side chain-backbone hydrogen bonds participate in formation of leucine zipper coiled coils?
The leucine zipper proteins are a group of transcriptional regulators that dimerize to form a DNA binding domain. It has been proposed that this dimerization results from the hydrophobic association of the alpha-helices of two leucine zipper monomers into a coiled coil. We propose a model for a coiled coil based on a periodic hydrophobic-hydrophilic amino acid motif found in the leucine zipper ...
متن کاملAlanine Zipper-Like Coiled-Coil Domains Are Necessary for Homotypic Dimerization of Plant GAGA-Factors in the Nucleus and Nucleolus
GAGA-motif binding proteins control transcriptional activation or repression of homeotic genes. Interestingly, there are no sequence similarities between animal and plant proteins. Plant BBR/BPC-proteins can be classified into two distinct groups: Previous studies have elaborated on group I members only and so little is known about group II proteins. Here, we focused on the initial characteriza...
متن کامل