NeXtProt is a comprehensive knowledge database focused on human proteins. It provides detailed information about the protein-coding genes in the human genome, including their sequences, functions, localization, interactions, and involvement in various biological processes and diseases.
Neighbor-net is a computational method used in phylogenetics to construct phylogenetic networks, which represent the evolutionary relationships among a set of species or sequences. Unlike traditional tree-based representations, which assume that evolution occurs in a strictly branching fashion, Neighbor-net can accommodate more complex evolutionary histories that may include events such as hybridization, horizontal gene transfer, or reticulate evolution.
Nesfatin-1 is a protein that is derived from the precursor molecule NEFA (nucleobindin-2). It is primarily known for its role in regulating appetite and energy homeostasis. Nesfatin-1 is produced in various tissues, including the hypothalamus, which is a key brain region involved in hunger and satiety. Research has indicated that nesfatin-1 can decrease food intake and promote feelings of fullness (satiety).
A nested gene is a type of gene that is located within the intron or coding region of another gene, meaning it is positioned inside the larger gene's sequence. This arrangement can occur in both prokaryotic and eukaryotic organisms, though it is more commonly studied in eukaryotes. Nested genes can arise through a variety of mechanisms, such as gene duplication, retrotransposition, or other evolutionary processes.
Nested polymerase chain reaction (nested PCR) is a modification of the standard polymerase chain reaction (PCR) technique that is designed to increase the specificity and sensitivity of the amplification of a target DNA sequence. It involves two consecutive rounds of PCR using two sets of primers. ### Steps Involved in Nested PCR: 1. **First Round of PCR**: - The first set of primers (outer primers) is used to amplify a larger target region of the DNA.
Neuropeptides are small protein-like molecules (peptides) used by neurons to communicate with each other. They play a significant role in brain function and can influence a wide variety of physiological processes including pain perception, stress response, appetite regulation, and neuroendocrine function. Neuropeptides are synthesized in the cell body of neurons and then transported to the nerve terminals, where they are stored in vesicles.
Nicking enzymes, also known as nicking endonucleases, are a type of enzyme that can introduce a single-strand break, or "nick," in a DNA molecule. These enzymes recognize specific DNA sequences and cleave one of the two strands, leaving the other strand intact. This is in contrast to restriction enzymes, which typically cut both strands of DNA at specific sequences, resulting in double-strand breaks.
The Nicking Enzyme Amplification Reaction (NEAR) is a molecular biology technique used for the amplification of nucleic acids, similar to the more widely known polymerase chain reaction (PCR). NEAR is notable for its use of nicking endonucleases, which are enzymes that introduce single-strand breaks or "nicks" in DNA at specific sequences.
The Nif gene refers to a set of genes involved in nitrogen fixation, primarily found in certain bacteria and archaea. Nitrogen fixation is the process by which atmospheric nitrogen (N₂) is converted into a form that can be utilized by living organisms, primarily ammonia (NH₃). This process is critical for the synthesis of amino acids and nucleotides, which are essential for life.
NlaIII is a restriction enzyme, which is an endonuclease that recognizes specific nucleotide sequences in DNA and cleaves the DNA at or near these sites. Specifically, NlaIII recognizes the palindromic sequence "G***C" and cuts between the G and C nucleotides, yielding specific DNA fragments. Restriction enzymes like NlaIII are widely used in molecular biology for cloning, DNA manipulation, and various genetic engineering applications.
The term "nonribosomal code" generally refers to the process by which nonribosomal peptides and other biomolecules are synthesized without the involvement of ribosomes, which are the cellular machinery primarily responsible for protein synthesis through the translation of mRNA. In contrast to the ribosomal code, which is based on the triplet codon system that translates nucleic acid sequences into proteins, nonribosomal synthesis occurs through a different mechanism.
Nonribosomal peptides are a class of peptides that are synthesized in cells by nonribosomal peptide synthetases (NRPSs), which are large multi-modular enzyme complexes. Unlike ribosomal peptides, which are produced through the classical ribosomal translation of messenger RNA, nonribosomal peptides are synthesized from amino acids in a sequence that is determined by the NRPSs, not by mRNA templates. This allows for a greater diversity of structures and modifications.
Nonsynonymous substitution refers to a type of genetic mutation that leads to a change in the amino acid sequence of a protein. Specifically, it occurs when a single nucleotide change (mutation) in DNA results in the coding of a different amino acid in the protein that is produced. This is in contrast to synonymous substitutions, which do not alter the amino acid sequence due to the redundancy of the genetic code.
A nuclear gene is a segment of DNA located within the nucleus of a eukaryotic cell, which encodes information for the synthesis of proteins or functional RNA molecules. Nuclear genes are distinct from mitochondrial or plastid genes, which are found in mitochondria and chloroplasts, respectively. Here are some key points regarding nuclear genes: 1. **Structure**: Nuclear genes are composed of exons (coding regions) and introns (non-coding regions).
Nucleic acid hybridization is a molecular biology technique used to identify, analyze, or manipulate nucleic acids (DNA or RNA) by allowing complementary strands to bind together. This process occurs when two single strands of nucleic acids (either DNA or RNA) come together and form a double-stranded molecule through base pairing.
Nucleic acid methods refer to a variety of techniques and processes used to analyze, manipulate, and study nucleic acids, which are the molecules that carry genetic information in living organisms. The two primary types of nucleic acids are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). These methods are essential in molecular biology, genetic research, diagnostics, and biotechnology.
A nucleic acid sequence is a series of nucleotides, which are the basic building blocks of nucleic acids like DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base. The sequence of these nucleotides determines the genetic information carried by the nucleic acid.
Nucleic acid thermodynamics is a field of study that focuses on the thermodynamic principles governing the stability, folding, and interactions of nucleic acids such as DNA and RNA. It encompasses the principles of energy changes, enthalpy, entropy, and free energy that dictate how nucleic acids behave in different conditions, including their stability under varying temperatures, concentrations, and ionic environments.
Nucleofection is a specialized technique used to introduce nucleic acids (DNA or RNA) into cells by utilizing an electrical field to facilitate the uptake of the genetic material. This method is particularly effective for difficult-to-transfect cell types that are less amenable to traditional transfection methods, such as lipofection or viral transduction.
A nucleosome is the fundamental unit of chromatin, which is the structural material of chromosomes in eukaryotic cells. Nucleosomes play a critical role in the packaging of DNA within the nucleus and in the regulation of gene expression. Each nucleosome consists of a core of histone proteins around which DNA is wrapped.