清华大学：《生物化学》课程PPT教学课件（英文版）Chapter Amino Acids, Peptides, and Proteins

Where are we? Welcome to Biology Biology is the science oflife Welcome to biochemistry Biochemistry is the study of chemical aspect of biology Welcome to the protein World Proteins are the workhorse molecules and major players of life

Welcome to Biology -Biology is the science of life Welcome to Biochemistry -Biochemistry is the study of chemical aspect of biology Welcome to the Protein World -Proteins are the workhorse molecules and major players of life Where are we?

about myself Xiangjun(Frank)Liu Ph. D in Molecular biology, ms in Biochemistry and eecs Tel:62792997Email:frankliu@tsinghua.edu.cn About the tas XinmiaoFu,62789386,fuxinmiao00@mails.tsinghua.edu.cn MingjieLiu,62772241,liumingjie99@mails.tsinghua.edu.cn about my classes 20%Quiz--taken at the beginning of the 3 rd class 30% Paperdue 12/01(hard copy, soft one by email, both to TA) 50% Final Exam QA Sessions: This, next and the last Thursday: 3-5pm, 5 253 http://166.111.16.113o校园网络

About Myself Xiangjun (Frank) Liu Ph.D. in Molecular Biology, MS in Biochemistry and EECS Tel: 62792997 Email: frankliu@tsinghua.edu.cn About the TAs Xinmiao Fu, 62789386, fuxinmiao00@mails.tsinghua.edu.cn Mingjie Liu, 62772241, liumingjie99@mails.tsinghua.edu.cn About My Classes 20% Quiz—taken at the beginning of the 3rd class 30% Paper—due 12/01 (hard copy, soft one by email, both to TA) 50% Final Exam QA Sessions: This, next and the last Thursday: 3-5pm, 强斋253 http://166.111.16.113 or 校园网络

Chapter 5 Amino Acids, Peptides, and Proteins 0. GeneralIntroduction Proteins are polymers(多聚体) of amino acids. 20 amino acids(l ) millions of proteins with different properties and activities Protein structures are studied at primary, secondary, tertiary and quaternary levels a helix, B sheets, globular, complexes, denaturation and folding. Proteins have widely diverse forms and functions enzymes酶, hormones(激素荷尔蒙, antibodies(抗体) transporters(转运蛋 白, muscle(肌肉) lens protein of eyes(眼睛晶状体), spider webs(蜘蛛 网) rhinoceros horn(犀牛角 antibiotics(抗生素) mushroom poisons(蘑菇毒素)

Proteins are polymers(多聚体) of amino acids. -20 amino acids (氨基酸) ➔ millions of proteins with different properties and activities. Protein structures are studied at primary, secondary, tertiary and quaternary levels. - helix,  sheets, globular, complexes, denaturation and folding. Proteins have widely diverse forms and functions. -enzymes(酶), hormones(激素,荷尔蒙), antibodies(抗体),transporters(转运蛋 白),muscle(肌肉),lens protein of eyes(眼睛晶状体), spider webs(蜘蛛 网),rhinoceros horn(犀牛角),antibiotics(抗生素),mushroom poisons(蘑菇毒素). 0. General Introduction Chapter 5 Amino Acids, Peptides, and Proteins

A few examples on protein diversity. Fireflies emit light catalyzed by luciferase(荧光素酶) with atP

Fireflies emit light catalyzed by luciferase（荧光素酶） with ATP A few examples on protein diversity…

Erythrocytes(红细胞) contain a large amount of hemoglobins(血红蛋白), the oxygen- transporting protein

Erythrocytes（红细胞） contain a large amount of hemoglobins（血红蛋白）, the oxygen-transporting protein

(c) The protein keratin(角蛋白) is the chief structural components of hair, scales, horn, wool, nails and feathers

The protein keratin （角蛋白） is the chief structural components of hair, scales, horn, wool, nails and feathers

1. All natural proteins were found to be built from a repertoire of 20 standard a-amino acids The earliest studies of proteins focused on the free amino acids derived from these proteins. The lst amino acid(asparagine) was discovered in 1806 from asparagus(a green vegetable). The last(threonine)was not identified until 1938 All the amino acids were given a trivial(common) name. Glutamate from wheat gluten(sticky). Tyrosine from cheese(“ tyros” in greek

1. All natural proteins were found to be built from a repertoire of 20 standard -amino acids The earliest studies of proteins focused on the free amino acids derived from these proteins. •The 1st amino acid (asparagine) was discovered in 1806 from asparagus (a green vegetable). •The last (threonine) was not identified until 1938! •All the amino acids were given a trivial (common) name. Glutamate from wheat gluten (sticky). Tyrosine from cheese (“tyros” in Greek)

1.1 The 20 a-amino acids share common structural features Each has a carboxyl group and an amino group (but one has an imino group in proline) bonded to the same carbon atom designated as the a carbon ∈ 6 5 2 CH2—CH2—CH2—cH2—cH—COO +NH 13 +NH3 Lysine In protein chemistry, we use Greek letter nomenclature. To find all greek letters, go to http://www.astro.uiuc.edu/kaler/sow/greek.html

1.1 The 20 -amino acids share common structural features. •Each has a carboxyl group and an amino group (but one has an imino group in proline) bonded to the same carbon atom, designated as the - carbon. In protein chemistry, we use Greek letter nomenclature. To find all Greek letters，go to： http://www.astro.uiuc.edu/~kaler/sow/greek.html

.Each has a different side chain(or r group R=“ Remainder of the molecule”) COo 3

•Each has a different side chain (or R group, R=“Remainder of the molecule”)

The a-carbons for 19 of them are asymmetric (or chiral), thus being able to have two enantiomers. Glycine has no chirality RS system re-viSited( Chapter 3, p60) The priorities of some common substituents are OCH2>-OH>-NH2>-C00H>-CHO>-CH2OH>-CH3>-H The chiral atom is viewed with the group of lowest priority pointing away from the viewer. If the priority of the other three groups decreases in clockwise order. the configuration isR(right); if in counterclockwise order, the configuration isL(eft”) CoO COO HRN O 0 NH3 13 CH3 L-Alanine D-Alanine (a

The -carbons for 19 of them are asymmetric (or chiral), thus being able to have two enantiomers. Glycine has no chirality. RS system re-visited (Chapter 3, p60): The priorities of some common substituents are -OCH2 > -OH > -NH2 > -COOH > -CHO > -CH2OH > -CH3 > -H The chiral atom is viewed with the group of lowest priority pointing away from the viewer. If the priority of the other three groups decreases in clockwise order, the configuration is R (“right”); if in counterclockwise order, the configuration is L (“left”)