Unformatted text preview: Found at turns or bends, which are on surface of proteins. Aliphatic Ser Ile EX: very polar nonpolar Gln Asp Glu Ser Lys Ala Aromatic big greasy phenyl ring behind it is quite hydrophobic (nonpolar) and dominates its interactions. Thus it is essentially a hydrophobic nonpolar aa, but one that dabbles with polar H bonds. Trp Phe Tyr Thr pKa = 10.46 Hydroxyl pKa = 12.48 pKa = 10.5 Leu Metet Asn Gln Glu Asp Lys Arg are restricted in the conformation the chain can adopt. ***more difficult for these aa’s to adopt α-helical conformation, but it is easier and preferred for them to lie within beta sheets he S atom is largely non-reactive, thus Met effectively substitutes well with true aliphatic aa’s. pKa = 3.9 Acidic AA’s pKa = 4.07 side chain nearest to protein main chain (hydrocarbon tail) Charged Amides Basic AA’s...
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- Spring '10
- Amino Acids, Glu, Disulfide bond, Thiol, aliphatic HydrophobicPolar Ser