프롤린 Proline

단백질 ≫ 아미노산 ≫ 아미노산 합성

프롤린 Proline

- Gluamic acid, glutamine
- Aspartic acid, asparagine
- serine, threonine, glycine, valine
- alanine, leucine, isoleucine
- lysine, arginine, histidine, proline
- methionine, Cysteine
- Tyrosine, Phenylalanie, Tryptophan

L-프롤린은 프롤라민 ·프로타민 ·카제인 ·젤라틴 등 여러 단백질에 함유
- Gluamic acid로 부터 만들어짐
- 콜라겐의 주성분
식물 속에서는 피롤린을 거쳐 알칼로이드의 아트로핀이나 니코틴이 변화
프롤린 자체에는 맛이 있는데 프롤린과 당을 가열하면 아미노카르보닐 반응이 일어나, 좋은 향기가 나며 갈색으로 착색, 이를 이용하 여 빵 제조에 사용

The distinctive cyclic structure of proline's side chain locks its backbone dihedral angle at approximately −75°, giving proline an exceptional conformational rigidity compared to other amino acids. Hence, proline loses less conformational entropy upon folding, which may account for its higher prevalence in the proteins of thermophilic organisms. Proline acts as a structural disruptor in the middle of regular secondary structure elements such as alpha helices and beta sheets; however, proline is commonly found as the first residue of an alpha helix and also in the edge strands of beta sheets. Proline is also commonly found in turns, which may account for the curious fact that proline is usually solvent-exposed, despite having a completely aliphatic side chain. Because proline lacks a hydrogen on the amide group, it cannot act as a hydrogen bond donor, only as a hydrogen bond acceptor. The distinct side chain/amine group interactions allow proline to aid in the formation of beta turns and also explains why it is not apparent in alpha helices...

A plastic ball-and-stick model of a proline molecule
Multiple prolines and/or hydroxyprolines in a row can create a polyproline helix, the predominant secondary structure in collagen. The hydroxylation of proline by prolyl hydroxylase (or other additions of electron-withdrawing substituents such as fluorine) increases the conformational stability of collagen significantly. Hence, the hydroxylation of proline is a critical biochemical process for maintaining the connective tissue of higher organisms. Severe diseases such as scurvy can result from defects in this hydroxylation, e.g., mutations in the enzyme prolyl hydroxylase or lack of the necessary ascorbate (vitamin C) cofactor.

Sequences of proline and 2-aminoisobutyric acid (Aib) also form a helical turn structure
In 2006, scientists at ASU discovered that solutions of TiO2 illuminated with ultraviolet radiation can serve as an extremely cost-effective and accurate protein cleavage catalyst. The TiO2 catalyst preferentially and rapidly cleaves protein at sites where proline is present, while taking much longer to degrade the protein from its endpoints.[3]

Peptide bond formation with incoming Pro-tRNAPro is considerably slower than with any other tRNAs, which is a general feature of N-alkylamino acids.[4]

  
 
 

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