Asp,D,天冬氨酸;Glu,E谷氨酸 Negatively charged R groups COO COO H3N—C-HH3N-C-H CH2 CH2 COO CH2 COo Aspartate Glutamate
Asp, D,天冬氨酸; Glu, E,谷氨酸
2.5 Hydropathy index values reflect the tendency of an amino acid to seek a hydrophilic environment(-"values )or a hydrophobic environment(“+” values) Properties and Conventions Associated with the Standard Amino Acids K values Abbrevated Hydropathy Occurrence NHi) (R group) in proteins (%) Nonpolar, aliphatic R groups Glycine 2.34 9,69 601 1.8 Valine 2.32 9.62 597 131 9.60 5.98 Isoleucine 131 Methionine Met M 149 2.28 9.21 5.74 .9 2.3 Aromatic R groups Phenylalanine Phe F 1.83 9.13 5.48 2.8 Tyrosine 181 2.20 9.11 10.0 5.66 3.2 Tryptophan Polar, uncharged 105 9.15 -0.8 6.8 Proline sPTc 6.48 Threonine 119 2.11 9.62 Cysteine 1.96 8.18 132 2.02 8.8o 5.41 3.5 Glutamine 146 9.13 5.65 4.2 8.95 10.5 9.74 Histidine 9.17 759 Arginine 9,04 12.48 1D.76 negatively charged Aspartate 9.60 3.65 2.7 -3.5 Glutamate 147 4.25 aq seous enwirboninen t dropalubs, tor an dyardphpbic et oo R ent s: values, ses c taper asz. tom t yee g. oolite. R. Eid]K 'Average occurrence in over 1150 proteins. From Doolittle, R F(1989) Redundancies in protein sequences. In Prediction of Protein Structure and the Principles of Protein Conformation(Fasman, G D, ed) Plenum Press, NY, pp. 599-623
2.5 Hydropathy index values reflect the tendency of an amino acid to seek a hydrophilic environment (“-” values ) or a hydrophobic environment (“+” values)
3. Nonstandard amino acids are found in certain proteins, generally as a result of post-translational modifications. These modifications are made after the standard amino acids have be ted inte 4-Hydroxyglutamate and 5-hydroxylysine in collagen(E) y-carboxyglutamate is found in the blood-clotting prothrombin(凝血酶原, an enze) Desmosine(锁链素) is a covalent linkage made from four Lys side chains in elastin(弹性蛋白) selenocysteine(硒代半胱氨酸, sulfur-> selenium) is found in many enzymes(having been recognized as the 2lst amino acid in ribosome-mediated protein synthesis! ) Many additional nonstandard amino acids are found in cells, but not in proteins(e.g, ornithine鸟氨酸 and citrulline瓜氨酸, intermediates in amino acid metabolism)
3. Nonstandard amino acids are found in certain proteins, generally as a result of post-translational modifications. •These modifications are made after the standard amino acids have been incorporated into proteins. •4-Hydroxyglutamate and 5-hydroxylysine in collagen(胶原). • g-carboxyglutamate is found in the blood-clotting prothrombin (凝血酶原,an enzyme). •Desmosine (锁链素) is a covalent linkage made from four Lys side chains in elastin (弹性蛋白). •Selenocysteine (硒代半胱氨酸, sulfur->selenium) is found in many enzymes (having been recognized as the 21st amino acid in ribosome-mediated protein synthesis!). •Many additional nonstandard amino acids are found in cells, but not in proteins (e.g., ornithine鸟氨酸and citrulline瓜氨酸, intermediates in amino acid metabolism)
COo HO-C CHo OOC-CH-CH2-CH-COo H2C CH--COO tNH. y-Carboxyglutamate 4-Hydroxyproline COo HgN-CH2CH-CH2-CH2-CH-Coo (CH2)3 NH OH t NHa CH-(CH2)2 (CH2C 5-Hydroxylysine OOC COO (CH2)4 CHa-NH--CH2--CH2--CH2--CH2-CH--Coo NHs HON COO 6-N-Methyllysine Desmosine HSe-CH2-CH-Co0 FNH (a) Selenocysteine
H3N-CH2CH2CH2-CH--COO NH 3 Ornithine H2N—C-N—CH2—CH。—CH。 CH-COC O H NH, Citrulline (b)