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proteopedia linkproteopedia linkקורס חלבונים מבנה וקישור תכנית רוטשילד ויצמן
מרצה:שירלי דאובה
מבנה הקורס
מבנה ראשוני של חלבון
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In biochemistry, the primary structure of a biological molecule is the exact specification of its atomic composition and the chemical bonds connecting those atoms (including stereochemistry). For a typical unbranched, un-crosslinked biopolymer (such as a molecule of DNA, RNA, or typical intracellular protein), the primary structure is equivalent to specifying the sequence of its monomeric subunits, e.g., the nucleotide or peptide sequence.
Primary structure is sometimes mistakenly termed primary sequence, but there is no such term, as well as no parallel concept of secondary or tertiary sequence. By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end, while the primary structure of DNA or RNA molecule is reported from the 5' end to the 3' end.
The primary structure of a nucleic acid molecule refers to the exact sequence of nucleotides that comprise the whole molecule. Frequently, the primary structure encodes motifs that are of functional importance. Some examples of sequence motifs are: the C/D[1]
and H/ACA boxes[2]
of snoRNAs, Sm binding site found in spliceosomal RNAs such as U1, U2, U4, U5, U6, U12 and U3, the Shine-Dalgarno sequence,[3]
the Kozak consensus sequence[4]
and the RNA polymerase III terminator.[5]
מבנה שניוני של חלבון
מבנה שלישוני של חלבון
חלק 1
חלק 2
חלק3
מבנה רביעוני
קואופרטיביות ואלוסטריה והסיפור של המוגלובין
קביעת מבנה - שיטות לאנליזה של חלבונים
סיפור האינסולין
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Insulin is a hormone that controls carbohydrate metabolism and storage in the human body. The body is able to sense the concentration of glucose in the blood and respond by secreting insulin, which is produced by beta cells in the pancreas. Synthesis of human insulin in E. coli is important to producing insulin for the treatment of type 1 diabetes. Proinsulin (Pins) is processed by several proteases in the Golgi apparatus to form insulin which is shorter by 35 amino acids. DPI is a monomeric despentapeptide (B26-B30) Ins analogue. DTRI is a monomeric destripeptide (B28-B30) Ins analogue. DHPI is for desheptapeptide (B24-B30) Ins. LIns is a
egume Ins.
Insulin is made up of two pieces called the A- and B-chain, shown above in blue and green respectively. These two chains are joined by disulfide bonds, which are shown in yellow. This single piece made up of the A- and B-chains is the active form of the insulin hormone. This is the form that binds the insulin receptor on fat or muscle cells in the body, singling them to take up glucose, or sugar, from the blood and save it for later.
Insulin is able to pair-up with itself and form a dimer by forming hydrogen bonds between the ends of two B-chains. These are shown above in white. Then, 3 dimers can come together in the presence of zinc ions and form a hexamer. Insulin is stored in the in the body. This the hydrophobic (gray) and polar (purple) parts of an insulin monomer at a pH of 7. It is believed that the hydrophobic sections on the B-chain cause insulin aggregation which initially caused problems in the manufacture and storage of insulin for pharmaceutical use.
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For additional details see
Insulin Structure & Function.
3D structures of Insulin (Updated on 11-June-2015)
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