111生物化学理论课件@中科大02氨基酸的结构2008

FindMod tool
http://us.expasy.org/tools/findmod/findmod_masses.html
Phosphorylation (磷酸化)：
Tyr
Ser
Thr
Glucosylation (糖基化)
N-Glucosylation: N O-Glucosylation: S/T
作业 请查找下列修饰发生的残基位点：
Amidation (氨基化) Methylation (甲基化) Acetylation (乙基化) Dimethylation (二甲基化)
பைடு நூலகம்
L-form: CORN, clockwise
A C D E F G H I K L M
Ala Cys Asp Glu Phe Gly His Ile Lys Leu Met
Alanine Cysteine Aspartic acid Glutamic acid Phenylalanine Glycine Histidine Isoleucine Lysine Leucine Methionine
8. Proteins are doing many things in the cell: 1) Catalyze reactions (enzymes); 2) Provide structural integrity (structural proteins); 3) Transport molecules (transporters); 4) Provide movement (cytoskeleton); 5) Regulation (regulatory factors) …
The ball-and-stick model of all 20 amino acids
C: grey O: red N: blue H: white S: orange
Cys
Ala
Arg Asn Asp
Cys
Gln
Glu
Gly
His Tyr Val
Ile
Leu
Lys
Met
Phe
Pro
Ser
From D. Wetlaufer, Adv. Protein Chem. (1962) 17:303-390. © 1962 Academic Press
碱性氨基酸: H, K, R (组、赖、精)
酸性氨基酸: D, N, E, Q
D and E are strongly acidic, while N and Q polar (极性) but not charged. All prefer exterior (表面) of protein
脂肪族氨基酸：G, A, V, L, I
含羟基或巯基侧链的氨基酸: S, C, T, M
Cys
Ser
S-Met
Se-Met
环状氨基酸: P
芳香族氨基酸: F, Y, W
Absorption spectra of the aromatic (芳香族) amino acids in the near-ultraviolet (近紫外) region
•Neutral, Nonpolar Amino acids: •Tryptophan •Phenylalanine •Glycine •Alanine •Valine •Isoleucine •Leucine •Methionine •Proline
Properties of Amino Acids
Primary The four levels of protein structure
Secondary
Tertiary
Quaternary
The primary structure of bovine insulin (胰岛素).
Disulfide bond (二硫键)
Structure of preproinsulin (胰岛素原前体) and its conversion to insulin.
Proteolytic enzymes (蛋白水解酶) (proteases, 蛋白酶):
http://us.expasy.org/tools/peptidecutter/
Glr1
2, amino acids: structure and property
Stereoisomers (立体异构体) of α-amino acids
2.1 20种氨基酸的结构和性质（3学时）
1, proteins: synthesis and degradation 2, amino acids: structure and property
参考书：
1, Introduction to Protein Structure, Carl Branden & John Tooze, 2nd Edition, by Garland Publishing, Inc. 2, GENES, VIII, Benjiamin Lewin, by Pearson Prentice Hall.
Useful websites:
1, The ExPASy (Expert Protein Analysis System): http://us.expasy.org/
2, National Center for Biotechnology Information (NCBI) http://www.ncbi.nlm.nih.gov/ Pubmed, Entrez, Blast, …
Translation of an RNA message into a protein.
5’---3’
N-----C
Gene VIII, B. Lewin
Gene VIII, B. Lewin
Proteins –
1. Biopolymers (called polypeptides) of L-amino acids.
Essential Amino Acids in Mammals (哺乳动物)
Non-Essential Amino Acids in Mammals
Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine FHI, LWKR, MTV
Thr
Trp
•Acidic Amino Acids: •Aspartic acid •Glutamic acid
•Basic, Polar Amino acids: •Lysine •Arginine •Histidine
•Neutral, Polar Amino acids: •Tyrosine •Serine •Threonine •Asparagine •Glutamine •Cysteine
Family health international, Last work remaining, MTV
Alanine, Asparagine, Aspartate, Cysteine, Glutamate, Glutamine, Glycine, Proline, Serine, Tyrosine
2. Joined via peptide bonds.
3. Only L-amino acids (rare D-form)
4. Putting amino acids together by translation. 5. Translation relies on the genetic code, 3Nt specify 1Res. 6. Different proteins have different sequences---The primary sequence determines the 3-D structure
天冬酰胺 脯氨酸 谷氨酰胺 精氨酸 丝氨酸 苏氨酸 缬氨酸 色氨酸 酪氨酸
X: undetermined/any amino acid
Alphabets that do NOT represent any amino acid:
J, O and U
10 amino acids should be provided in the diet (essential) （必需氨基酸）
3, IMB-Jena Amino Acid Repository: http://www.imb-jena.de/IMAGE_AA.html
1, proteins: synthesis and degradation
The Central Dogma
1. 单程性 2. 共线性
Crick F. Central dogma of molecular biology. Nature. 1970 Aug 8;227(5258):561-3
丙氨酸 半胱氨酸 天冬氨酸 谷氨酸 苯丙氨酸 甘氨酸 组氨酸 异亮氨酸 赖氨酸 亮氨酸 甲硫氨酸、蛋氨酸
N P Q R S T V W Y B Z
Asn Pro Gln Arg Ser Thr Val Trp Tyr Asx Glx
Asparagine Proline Glutamine Arginine Serine Threonine Valine Tryptophan Tyrosine Asp or Asn Glu or Gln
7. The differences between a polypeptide and a protein are:
1) Polypeptide refers simply to a chain of amino acids. 2) Protein refers to the chain of amino acids after it folds properly and is, in some cases, modified. 3) Proteins may consist of more than one polypeptide chain.
平均分子量：～120
Rare amino acids:
Post-translational modifications
Phosphorylation (磷酸化) Glucosylation (糖基化) Glutathionylation (谷胱甘肽化) Amidation (氨基化) Methylation (甲基化) Acetylation (乙基化) Dimethylation (二甲基化)