Sional (0D) fullerene, one-dimensional (1D) carbon nanotubes (CNTs) and two-dimensional (2D) graphene. NPs are small enough to enter almost all compartments of the organism, including cells and organelles, which will complicate the pattern of protein interactions. When NPs are introduced in a living organism, their surfaces may perturb the native structure of proteins [8] as well as self-assembly pathway of peptides or proteins [9,10]. A lot of researches indicate NPs can interfere with amyloid formation [11?7]. However, whether nanomaterials inhibit or promote amyloid formation is still a controversial issue. Experimental studies indicate that the diverse effects of Title Loaded From File fullerene [11?4], carbon nanotube [15,16], graphite [17,18] and mica [17] on amyloid formation depend on the intrinsic property of the peptide and the surface, and the way they interact with each other.Catalysis of the process may occur by increasing local protein concentration and accelerating the rate of nucleation on the NP surface, whereas tight binding or a large particle/protein surface area may lead to inhibition of protein aggregation [19]. Title Loaded From File Despite these observations, the detailed processes underlying the association of peptides or proteins on surfaces of NPs have so far remained elusive. It is well known that amyloidosis is a class of disease defined by the misfolding and aggregation of functional protein precursors into fibrillar states. Amyloid fibers contribute to the pathology of many diseases, including type II diabetes, Alzheimer’s disease, and Parkinson’s disease [20?4]. In these disorders, amyloid fibers are present in affected tissues. However, it has become clear that intermediate states, rather than mature 1315463 fibers, represent the cytotoxic species [25,26]. Islet amyloid polypeptide (IAPP, or amylin) is a hormone coexpressed with insulin by pancreatic islet b-cells and its abnormal aggregation into amyloid fibrils is a hallmark of type II diabetes [27]. As for type II diabetes, although the molecular mechanism of its pathogenesis remains elusive, there is also evident that the key pathological species are transient bsheet-rich oligomers of IAPP, which therefore represent therapeutic targets for treatment of type II diabetes [26,28?0]. Due to the wide use of NPs in biomedicinal field, it is interesting and necessary to evaluate whether NPs affect the structure andInfluence of Nanoparticle on Amyloid Formationfunction of the proteins in human body, especially those proteins which are easier to misfold and aggregate, and further leading to the occurrence of related disease. Such information is not only valuable for design safe and effective nanoparticles, but also investigating the mechanism of protein misfolding disease. If NPs can inhibit the process of the formation of amyloid fibrils, they will have great potential to be used as valuable therapeutic materials to control amyloid diseases like Alzheimer’s disease [31?4]. However, if NPs promote the aggregation of peptides or proteins, it will cause toxicity. Therefore, in this work, we will present a systematic study to investigate how the oligomer of hIAPP22?8 forms and the effects of 23977191 different carbon NPs including graphene, single-wall carbon nanotube (SWCNT) and fullerene (C60) on the oligomer formation pathway. Our findings will give valuable information for further understanding the interaction between IAPP22?8 and carbon NPs, and provide insights into the safety of carbon nanomaterials when they enter.Sional (0D) fullerene, one-dimensional (1D) carbon nanotubes (CNTs) and two-dimensional (2D) graphene. NPs are small enough to enter almost all compartments of the organism, including cells and organelles, which will complicate the pattern of protein interactions. When NPs are introduced in a living organism, their surfaces may perturb the native structure of proteins [8] as well as self-assembly pathway of peptides or proteins [9,10]. A lot of researches indicate NPs can interfere with amyloid formation [11?7]. However, whether nanomaterials inhibit or promote amyloid formation is still a controversial issue. Experimental studies indicate that the diverse effects of fullerene [11?4], carbon nanotube [15,16], graphite [17,18] and mica [17] on amyloid formation depend on the intrinsic property of the peptide and the surface, and the way they interact with each other.Catalysis of the process may occur by increasing local protein concentration and accelerating the rate of nucleation on the NP surface, whereas tight binding or a large particle/protein surface area may lead to inhibition of protein aggregation [19]. Despite these observations, the detailed processes underlying the association of peptides or proteins on surfaces of NPs have so far remained elusive. It is well known that amyloidosis is a class of disease defined by the misfolding and aggregation of functional protein precursors into fibrillar states. Amyloid fibers contribute to the pathology of many diseases, including type II diabetes, Alzheimer’s disease, and Parkinson’s disease [20?4]. In these disorders, amyloid fibers are present in affected tissues. However, it has become clear that intermediate states, rather than mature 1315463 fibers, represent the cytotoxic species [25,26]. Islet amyloid polypeptide (IAPP, or amylin) is a hormone coexpressed with insulin by pancreatic islet b-cells and its abnormal aggregation into amyloid fibrils is a hallmark of type II diabetes [27]. As for type II diabetes, although the molecular mechanism of its pathogenesis remains elusive, there is also evident that the key pathological species are transient bsheet-rich oligomers of IAPP, which therefore represent therapeutic targets for treatment of type II diabetes [26,28?0]. Due to the wide use of NPs in biomedicinal field, it is interesting and necessary to evaluate whether NPs affect the structure andInfluence of Nanoparticle on Amyloid Formationfunction of the proteins in human body, especially those proteins which are easier to misfold and aggregate, and further leading to the occurrence of related disease. Such information is not only valuable for design safe and effective nanoparticles, but also investigating the mechanism of protein misfolding disease. If NPs can inhibit the process of the formation of amyloid fibrils, they will have great potential to be used as valuable therapeutic materials to control amyloid diseases like Alzheimer’s disease [31?4]. However, if NPs promote the aggregation of peptides or proteins, it will cause toxicity. Therefore, in this work, we will present a systematic study to investigate how the oligomer of hIAPP22?8 forms and the effects of 23977191 different carbon NPs including graphene, single-wall carbon nanotube (SWCNT) and fullerene (C60) on the oligomer formation pathway. Our findings will give valuable information for further understanding the interaction between IAPP22?8 and carbon NPs, and provide insights into the safety of carbon nanomaterials when they enter.
