Organization macromolecule complex
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The document discusses macromolecules, which are large molecules formed from smaller subunits called monomers, and categorizes them into four types: proteins, carbohydrates, lipids, and nucleic acids. It describes the formation of macromolecule complexes such as chromatin and ribosomes, detailing their structure, composition, and functions in biological processes. Additionally, it highlights the historical context of macromolecule research and their essential roles in cellular mechanisms.
Organization macromolecule complex
- 1. Organization of macromolecule complex By KAUSHAL KUMAR SAHU Assistant Professor (Ad Hoc) Department of Biotechnology Govt. Digvijay Autonomous P. G. College Raj-Nandgaon ( C. G. )
- 2. CONTENT INTRODUCTION OF MACROMOLECULE HISTORY OF MACROMOLECULE PROPERTIES TYPES OF MACROMOLECULE COMPLEX FORMATION EXAMPLE- Chromatin Ribosome CONCLUSION REFERENCES
- 3. INTRODUCTION A macromolecule is a very large molecule commonly created by polymerization of smaller subunits. In biochemistry, the term is applied to the four conventional biopolymers (nucleic acids, proteins, carbohydrates, and lipids), as well as non-polymeric molecules with large molecular mass such as macrocycles . The individual constituent molecules of macromolecules are called monomers (mono=single, meros=part). Small organic molecules are the basic stuff of life. Scientists call them monomers. Mono means one. When monomers (small molecules) are joined together, they form larger molecules called polymers. Poly means many. Think of the polymers as that brick wall. And when polymers are joined together, they form “giant” molecules called macromolecules. Macro means big.
- 4. HISTORY OF MACROMOLECULE The term macromolecule was coined by Nobel laureate Hermann Staudinger in the 1920s, although his first relevant publication on this field only mentions high molecular compounds (in excess of 1,000 atoms). At that time the phrase polymer, as introduced by Berzelius in 1833, had a different meaning from that of today: it simply was another form of isomerism for example with benzene and acetylene and had little to do with size.
- 5. TYPES OF MACROMOLECULE Macromolecules can be divided into 4 major categories : Proteins Carbohydrate Lipids Nucleic acid
- 6. COMPLEX FORMATION Hydrophobic interactions between membrane lipids and hydrophobic domains of the protein. α helix type protein mostly found. Both the amino and carboxyl terminus contains many polar or charged amino acids residue and are therefore hydrophilic. Segment in the center of protein contains hydrophobic, non polar amino acid residues. Phospholipids molecules lie on the protein surface, their head groups interacting with the polar amino acids residues at the inner and outer membrane- water interfaces and their side chains associated with the non polar residues. These annular lipids form a bilayer shell around the protein.
- 7. Tyr and Trp residue – membrane interface anchors. Lys, His, Arg- positively charged – present on cytoplasmic membrane. Membrane proteins contain one or more covalently linked lipids – like long chain fatty acid, isoprenoids, and sterols. Other interactions are ionic attraction between positively charged Lys residue in the protein and negatively charged lipid head groups contribute the stability. Plasma membrane glycoproteins are always oriented with the oligosaccharide bearing domain on the extracellular surface.
- 9. Chromatin Chromatin consists of DNA and Proteins The eukaryotic cell cycle produces remarkable changes in the structure of chromosomes. In nondividing eukaryotic cells (in G0) and those in interphase (Gl, S, and G2), the chromosomal material, chromatin, is amorphous and seems to be randomly dispersed in certain parts of the nucleus. In the S phase of interphase the DNA in this amorphous state replicates, each chromosome producing two sister chromosomes (called sister chromatids) that remain associated with each other after replication is complete. Chromatin consists of fibers containing protein and DNA in approximately equal proportions (by mass), along with a small amount of RNA. The DNA in the chromatin is very tightly associated with proteins called histones, which package and order the DNA to structural units called nucleosomes. Also found in chromatin are many non histone proteins, some of which help maintain chromosomes structure and others that regulate the expression of specific genes.
- 10. Histones are small, basic protein Found in the chromatin of all eukaryotic cells, histones have molecular weights between 1 1 ,000 and 21,000 and are very rich in the basic amino acids arginine and lysine (together these make up about one-fourth of the amino acid residues). All eukaryotic cells have five major classes of histones, differing in molecular weight and amino acid composition. Such modifications affect the net electric charge, shape, and other properties of histones, as well as the structural and functional properties of the chromatin, and they play a role in the regulation of transcription.
- 11. Nucleosome are fundamental organizational units of chromatin The eukaryotic chromosome depicted in represents the compaction of a DNA molecule about 105 pm long into a cell nucleus that is typically 5 to 10 pm in diameter. This compaction involves several levels of highly organized folding. Subjection of chromosomes to treatments that partially refold them reveals a structure in which the DNA is bound tightly to beads of protein, often regularly spaced. The beads in this "beads-on-a-string" arrangement are complexes of histones and DNA. The bead plus the correcting DNA that leads to the next bead form the nucleosome the fundamental unit of organization on which the higher-order packing of chromatin is built. The bead of each nucleosome contains eight histone molecules: two copies each of H2A, H2B, H 3, and H4. The spacing of the nucleosome beads provides a repeating unit typically of about 200 bp, of which 146 bp are bound tightly around the eight-part histone core and the remainder serve as linker DNA between nucleosome beads.
- 12. Types and properties of histone Histone H1. H2A H2B H3 H4 Molecular weight 21,130 13,960 13,774 15,273 11,236 Number of amino acid residues 223 129 125 135 102 Content of basic amino acids (% of total) Lys Arg 29.5 11.3 10.9 19.3 16.0 16.4 19.6 13.3 10.8 13.7
- 13. Nucleosome are Packed into successively Higher-0rder structures Wrapping of DNA around a nucleosome core compacts the DNA length about sevenfold. The overall compaction in a chromosome however, is greater than 10,000-fold-ample evidence for even higher orders of structural organization. In chromosomes isolated by very gentle methods, nucleosome cores seem to be organized into a structure called the 30 nm fiber. Organization in to 30 nm fibers does not extend over the entire chromosome but is punctuated by regions bound by sequence- specific (non histone) DNA-binding proteins. The 30 nm structure also seems to depend on the transcriptional activity of the particular region of DNA. The presence of topoisomerase II further emphasizes the relationship between DNA under winding and chromatin structure.
- 15. The Ribosome complex supramolecular Machine Bacterial ribosomes contain about 65%of rR NA and 35% of protein; they have a diameter of about 18 nm and are composed of two unequal subunits with sedimentation coefficients of 30S and 50S and a combined sedimentation coefficient of 70S. Both subunits contain dozens of ribosomal proteins and at least one large rRNA . Followug Zamecnik's discovery that ribosomes are the complexes responsible for protein synthesis and following elucidation of the genetic code, the study of ribosomes accelerated. I n the late 1960sMasayasu Nomura and colleagues demonstrated that both ribosomal subunit can be broken down into their RNA and protein components, then reconstituted in vitro. Under appropriate experimental conditions, the RNA and protein spontaneously reassemble to form 30S or 50S subunits nearly identical in structure and activity to native subunits. First, the traditional focus on the protein components of ribosomes as shifted. The ribosomal subunits are huge RNA molecules. In the 50S subunit, the 55 and 23S rRNAs form the structural core. The proteins are secondary elements in the complex, decorating the surface. Second and most important, there is no protein within 18 A of the active site for peptide bond formation.
- 17. The ribosomes of eukaryotic cells( other than mitochondrial and chloroplast ribosomes) are larger and more complex than bacterial ribosomes (Fig. 27-15), with a diameter of about 23 nm and a sedimentation coefflcient of about 80S. They also have two subunits, which vary in size among species but on average are 60S and 40S. A together, eukaryotic ribosomes contain more than 80 different proteins. The ribosomes of mitochondria and chloroplasts are somewhat smaller and simpler than bacterial ribosomes nevertheless ribosomal structure and function are strikingly similar in all organisms and organelles.
- 18. Conclusion Macromolecular complexes are naturally occurring machines inside cells. They consist of a handful to several thousand individual components, including proteins, DNA, carbohydrates and lipids, and perform diverse and vital tasks, such as translating the genetic code, converting energy or helping nerve cells communicate.
- 19. References BOOK- Lehninger Principle of Biochemistry – 5th edition – David L. Nelson and Michael M. Cox. INTERNET- http://en.wikipedia.org