A dataset of criteria on the use of thermal insulation solutions in building facades located in Norway, Portugal and Italy.

The building sector is responsible for a significant percentage of the energy consumption in Europe. The level of thermal insulation of the building envelope leads to decrease energy consumption, thus contributing towards a sustainable and efficient built environment. As a result, the choice of the most suitable thermal insulation solution to be applied both in new construction and in retrofitting of building facades is fundamental for a satisfactory thermal performance of the building. Nevertheless, the thermal insulation solution should not be chosen considering only the thermal performance, but rather based on a set of performance parameters (i.e., water resistance, fire performance, impact on the environment and human health, among others) and climate-related requirements. This data article includes a dataset on criteria adopted in three European countries (namely Norway, Portugal, and Italy) considering a PESTE analysis (i.e., criteria related to Political, Economic, Social, Technological, and Environmental questions). The main objective was to evaluate the knowledge and perception of people living and/or working in these countries about the use and the performance of thermal insulation solutions in building facades. To this aim a questionnaire was developed within the scope of the EEA Granted EFFICACY research project (November 2022 - February 2023), whose overall objective is to create a database that serves as a reference for the choice of thermal insulation solutions to be applied in building facades for thermal and energy performances optimization. This database contributes to systemize criteria and can be extended by other researchers or professionals in the area, as well as in other countries.

Determinants of the contractile properties in the embryonic chicken gizzard and aorta.

Smooth muscle is generally grouped into two classes of differing contractile properties. Tonic smooth muscles show slow rates of force activation and relaxation and slow speeds of shortening (V(max)) but force maintenance, whereas phasic smooth muscles show poor force maintenance but have fast V(max) and rapid rates of force activation and relaxation. We characterized the development of gizzard and aortic smooth muscle in embryonic chicks to identify the cellular determinants that define phasic (gizzard) and tonic (aortic) contractile properties. Early during development, tonic contractile properties are the default for both tissues. The gizzard develops phasic contractile properties between embryonic days (ED) 12 and 20, characterized primarily by rapid rates of force activation and relaxation compared with the aorta. The rapid rate of force activation correlates with expression of the acidic isoform of the 17-kDa essential myosin light chain (MLC(17a)). Previous data from in vitro motility assays (Rover AS, Frezon Y, and Trybus KM. J Muscle Res Cell Motil 18: 103-110, 1997) have postulated that myosin heavy chain (MHC) isoform expression is a determinant for V(max) in intact tissues. In the current study, differences in V(max) did not correlate with previously published differences in MHC or MLC(17a) isoforms. Rather, V(max) was increased with thiophosphorylation of the 20-kDa regulatory myosin light chain (MLC(20)) in the gizzard, suggesting that a significant internal load exists. Furthermore, V(max) in the gizzard increased during postnatal development without changes in MHC or MLC(17) isoforms. Although the rate of MLC(20) phosphorylation was similar at ED 20, the rate of MLC(20) dephosphorylation was significantly higher in the gizzard versus the aorta, correlating with expression of the M130 isoform of the myosin binding subunit in the myosin light chain phosphatase (MLCP) holoenzyme. These results indicate that unique MLCP and MLC(17) isoform expression marks the phasic contractile phenotype.

Conformational modulation of slow skeletal muscle troponin T by an NH(2)-terminal metal-binding extension.

Troponin T (TnT) is an essential element in the thin filament Ca(2+)-regulatory system controlling striated muscle contraction. Alternative RNA splicing generates developmental and muscle type-specific TnT isoforms differing in the hypervariable NH(2)-terminal region. Using avian fast skeletal muscle TnT containing a metal-binding segment, we have demonstrated a role of the NH(2)-terminal domain in modulating the conformation of TnT (Wang J and Jin JP. Biochemistry 37: 14519-14528, 1998). To further investigate the structure-function relationship of TnT, the present study constructed and characterized a recombinant protein in which the metal-binding peptide present in avian fast skeletal muscle TnT was fused to the NH(2) terminus of mouse slow skeletal muscle TnT. Metal ion or monoclonal antibody binding to the NH(2)-terminal extension induced conformational changes in other domains of the model TnT molecule. This was shown by the altered affinity to a monoclonal antibody against the COOH-terminal region and a polyclonal antiserum recognizing multiple epitopes. Protein binding assays showed that metal binding to the NH(2)-terminal extension had effects on the interaction of TnT with troponin I, troponin C, and most significantly, tropomyosin. The data indicate that the NH(2)-terminal Tx [4-7 repeats of a sequence motif His-(Glu/Ala)-Glu-Ala-His] extension confers a specific conformational modulation in the slow skeletal muscle TnT.

Cooperative interaction between developmentally regulated troponin T and tropomyosin isoforms in the absence of F-actin.

Troponin T (TnT) is the tropomyosin (Tm) binding subunit of the troponin complex that mediates the Ca(2+) regulation of actomyosin interaction in striated muscles. Troponin T isoform diversity is marked by a developmentally regulated acidic to basic switch that may modulate muscle contractility. We previously reported that transgenic expression of fast skeletal muscle TnT altered the cooperativity of cardiac muscle. In the present study, we have demonstrated that the binding of acidic TnT to troponin I is weaker than that of basic TnT. However, affinity chromatography experiments showed that Tm bound to acidic TnT with a greater affinity than to basic TnT, consistent with the significantly higher maximal binding of acidic TnT to Tm in solid phase binding assays. Competition and co-immunoprecipitation experiments demonstrated that the binding of TnT to Tm was cooperative in the absence of F-actin. The cooperativity between TnT molecules for Tm binding can be initiated by the conserved COOH-terminal T2 fragment of TnT. This indicates that the interaction of TnT with Tm induces a conformational change in Tm, promoting interaction of TnT with adjacent Tm dimers. This finding suggests a role for TnT and its acidic and basic isoforms in the cooperative release of the inhibition of striated muscle actomyosin interaction.

Acidic and basic troponin T isoforms in mature fast-twitch skeletal muscle and effect on contractility.

Developmentally regulated alternative RNA splicing generates distinct classes of acidic and basic troponin T (TnT) isoforms. In fast-twitch skeletal muscles, an acidic-to-basic TnT isoform switch ensures basic isoform expression in the adult. As an exception, an acidic segment in the NH2-terminal variable region of adult chicken breast muscle TnT isoforms is responsible for the unique exclusive expression of acidic TnTs in this muscle (O. Ogut and J.-P. Jin. J. Biol. Chem. 273: 27858-27866, 1998). To understand the relationship between acidic vs. basic TnT isoform expression and muscle contraction, the contractile properties of fibers from adult chicken breast muscle were compared with those of the levator coccygeus muscle, which expresses solely basic TnT isoforms. With use of Triton X-100-skinned muscle fibers, the force and stiffness responses to Ca2+ were measured. Relative to the levator coccygeus muscle, the breast muscle fibers showed significantly increased sensitivity to Ca2+ of force and stiffness with a shift of approximately 0.15 in the pCa at which force or stiffness was 50% of maximal. The expression of tropomyosin, troponin I, and troponin C isoforms was also determined to delineate their contribution to thin-filament regulation. The data indicate that TnT isoforms differing in their NH2-terminal charge are able to alter the sensitivity of the myofibrillar contractile apparatus to Ca2+. These results provide evidence linking the regulated expression of distinct acidic and basic TnT isoform classes to the contractility of striated muscle.

Developmentally regulated, alternative RNA splicing-generated pectoral muscle-specific troponin T isoforms and role of the NH2-terminal hypervariable region in the tolerance to acidosis.

The structure-function relationship of the alternative RNA splicing-generated NH2-terminal variable region of troponin T (TnT) is essential for understanding the physiological significance of developmental or muscle-specific TnT isoforms. Representing the hypervariable nature of the NH2-terminal region, a repeating transition metal-binding sequence (H(E/A)EAH)4-7 (Tx) has been found in chicken fast skeletal muscle TnT. In the present study, the developmentally regulated pectoral muscle-specific expression of this novel TnT isoform has been characterized. It was found that the variable amino terminus determined the isoelectric points of the TnT isoforms expressed, and the adult muscle-specific inclusion of the Tx sequence resulted in pectoralis TnTs, which were significantly more acidic in their NH2-terminal segment versus gastrocnemius TnTs. Experiments testing the effect of pH on TnT interaction with troponin I and tropomyosin indicated that although the interaction of acidic TnT isoforms with troponin I was less sensitive to the decrease of pH than the basic TnTs, the binding affinity of acidic TnT isoforms with tropomyosin was minimally affected by the decreased pH in contrast to basic TnT isoforms. Given that the majority of adult skeletal muscles express basic fast TnT isoforms, the switching between acidic and basic TnT isoforms may play a role in the functional adaptation of muscle to acidosis.

Developmentally regulated muscle type-specific alternative splicing of the COOH-terminal variable region of fast skeletal muscle troponin T and an aberrant splicing pathway to encode a mutant COOH-terminus.

Distinct from the cardiac and slow skeletal muscle troponin Ts, an alternative RNA splicing-generated COOH-terminal variable region exists in the fast skeletal muscle troponin T. Mutually exclusive splicing of exon 16 and 17 encoded sequence into the mature mRNA produces the alpha- and beta-isoform, respectively. By cloning and sequence analysis of large numbers of fast troponin T cDNAs, we have quantitatively demonstrated that expression of the exon 16-encoded structure is mature fast muscle-specific (its utilization ranges from null in neonatal mouse muscles to 97% in adult chicken pectoralis), indicating a functional adaptation to the contractile feature of muscle. An aberrant splicing of this variable region to exclude both exons 16 and 17 from the mRNA was found in neonatal mouse skeletal muscle by cloning and sequencing characterization of a full length fTnT cDNA. The unusual splicing of exon 18 and exon 15 in the mRNA sequence results in not only a deletion of the exon 16/17 segment but also a shift of the downstream translation reading frame to produce a troponin T polypeptide with mutant COOH-terminus. Similar to an abnormal splicing of cardiac troponin T caused by cis-mutation and a dominant allele causing human familial hypertrophic cardiomyopathy, this trans-factor-determined aberrant mRNA splicing pathway generates a truncated troponin T molecule lacking the developmentally regulated fast muscle-specific COOH-terminal domain, indicating potential etiopathological significance.

Expression, zinc-affinity purification, and characterization of a novel metal-binding cluster in troponin T: metal-stabilized alpha-helical structure and effects of the NH2-terminal variable region on the conformation of intact troponin T and its association with tropomyosin.

A repeating metal-binding (Cu2+ > Ni2+ > Zn2+ approximately Co2+) sequence [HE/AEAH]4 (Tx) has been recently identified in the NH2-terminal variable region of troponin T (TnT) isoforms specifically expressed in the breast but not leg muscles of the avian orders of Galliformes and Craciformes [Jin, J.-P., & Smillie, L. B. (1994) FEBS Lett. 341, 135-140]. In the present study, two expression plasmids were constructed to produce chicken TnT1 NH2-terminal fragments of 47 (N47) or 165 (N165) amino acids containing the Tx metal-binding cluster. The recombinant protein/peptide was expressed in Escherichia coli BL21(DE3)pLysS and purified by a highly effective Zn(2+)-affinity chromatography method. Amino acid analyses, NH2-terminal peptide sequencing, mass spectrometry and immunological identification confirmed the authenticity of the genetically engineered TnT fragments. In the presence of 2,2,2-trifluoroethanol, transition metals had significant effects on the secondary structure of TnT fragment N47, as shown by circular dichroism. N165 in non-denaturing buffer demonstrated alpha-helical content comparable to previous data from rabbit fast skeletal TnT fragment T1. Zn(2+)-binding avidity of the metal-binding TnT and its fragments demonstrated tertiary relationships between the NH2-terminal variable region and the COOH-terminal segment of the intact TnT protein. Solid-phase protein-binding assays established that Zn(2+)-binding to the Tx cluster induces epitopic structure changes in this NH2-terminal segment, further affecting other epitopic structures of intact TnT as well as the function of TnT's tropomyosin binding-sites. The results demonstrate that metal ion-binding to the Tx cluster reconfigures the overall conformation of TnT through structural relationships between the NH2-terminal variable region and other domains of the intact TnT molecule. Accordingly, the developmental and/or muscle type specific NH2-terminal structure of TnT isoforms may modulate the Ca(2+)-activation of muscle contraction.