In this task, you're given a paragraph and title from the research paper. Your task is to classify whether the given title is suitable or not for the research paper based on the given paragraph. Return "True" if title is proper according to paragraph else "False".

Q: Paragraph: During the replication cycle of Sindbis virus minus-strand synthesis stops normally at the time that plus-strand synthesis reaches a maximum rate. We have isolated and characterized revertants of ts24, a member of the A complementation group of Sindbis HR mutants, that we had demonstrated previously to have a temperature-sensitive defect in the regulation of minus-strand synthesis. These revertants of t&4 replicated efficiently at 40' but nevertheless retained the temperature sensitive defect in the regulation of minus-strand synthesis: they continued to synthesize minus strands late in the replication cycle at 40" but not at 30" and in the presence or absence of protein synthesis. Although failure to regulate the synthesis of minus strands resulted in continuous minus-strand synthesis and in the accumulation of minus strands, the rate of plus-strand synthesis was not increased concertedly. Minus strands synthesized after the rate of plus-strand synthesis had become constant were demonstrated to be utilized as templates for 26 S mRNA synthesis. Thus, the change from an increasing to a constant rate of plus-strand synthesis during the alphavirus replication cycle cannot be governed solely by the number of minus strands that accumulate in infected cells. We present a model for the preferential utilization of minus strands as a mechanism for the cessation of minus-strand synthesis that occurs normally during alphavirus replication. 
 Title: The Effect of Loss of Regulation of Minus-Strand RNA Synthesis on Sindbis Virus Replication

A: True
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Q: Paragraph: Many new RNA pseudoknot structures have been detected and proposed in the past year. Although we are still waiting for the first detailed structure of a pseudoknot, their role in processes such as translational autoregulation or ribosomal frameshifting has been extensively studied and is now well established. Pseudoknot structures appear to play a pivotal role in small subunit ribosomal RNA and in the noncoding regions of viral RNAs. There are also strong indications that RNA pseudoknots are highly suitable structural motifs for the recognition and binding of proteins. 
 Title: RNA pseudoknots

A: False
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Q: Paragraph: HKU1 is a human betacoronavirus that causes mild yet prevalent respiratory disease 1 , and is related to the zoonotic SARS 2 and MERS 3 betacoronaviruses, which have high fatality rates and pandemic potential. Cell tropism and host range is determined in part by the coronavirus spike (S) protein 4 , which binds cellular receptors and mediates membrane fusion. As the largest known class I fusion protein, its size and extensive glycosylation have hindered structural studies of the full ectodomain, thus preventing a molecular understanding of its function and limiting development of effective interventions. Here we present the 4.0 Å resolution structure of the trimeric HKU1 S protein determined using singleparticle cryo-electron microscopy. In the pre-fusion conformation, the receptor-binding subunits, S1, rest above the fusion-mediating subunits, S2, preventing their conformational rearrangement. Surprisingly, the S1 C-terminal domains are interdigitated and form extensive quaternary interactions that occlude surfaces known in other coronaviruses to bind protein receptors. These features, along with the location of the two protease sites known to be important for coronavirus entry, provide a structural basis to support a model of membrane fusion mediated by progressive S protein destabilization through receptor binding and proteolytic cleavage. These studies should also serve as a foundation for the structure-based design of betacoronavirus vaccine immunogens. Betacoronavirus S proteins are processed into S1 and S2 subunits by host proteases 5 . Like other class I viral fusion proteins, the two subunits trimerize and fold into a metastable pre-fusion conformation. The S1 subunit is responsible for receptor binding, while the S2 subunit mediates membrane fusion. Coronaviruses typically possess two domains within S1 capable of binding to host receptors: an amino (N)-terminal domain (NTD) and a carboxy (C)-terminal domain (CTD), with the latter recognizing protein receptors for SARS-CoV and MERS-CoV 6,7 . Although these individual domains have been structurally characterized, the organization of the complete spike has not yet been determined, preventing a mechanistic understanding of S protein function. Here, we present the structure of the HKU1 S protein ectodomain determined using cryo-electron microscopy (cryo-EM) to 4.0 Å resolution ( Fig. 1a and Extended Data Figs 1 and 2 and Extended Data Table 1 ). The protein construct contains a C-terminal T4 fibritin trimerization motif and a mutated S1/S2 furin-cleavage site (Extended Data Fig. 3 ). The S1 subunit adopts an extended conformation with short linkers between domains and sub-domains (Fig. 1b) . The S1 NTD (amino acids 14-297) has strong structural and sequence homology to the bovine coronavirus (BCoV) S1 NTD (Extended Data Fig. 4) , which recognizes acetylated sialic acids on glycosylated cell-surface receptors 8 . The glycan-binding site in the BCoV S1 NTD is conserved in the HKU1 S1 NTD and is located at the apex of the trimer, oriented towards target cells. Indeed, HKU1 S1 was recently shown to bind O-acetylated sialic 
 Title: Pre-fusion structure of a human coronavirus spike protein

A:
True
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