This has a regular coiled structure like a spring, with the R groups pointing towards the outside of the helix. Hydrogen (H) bonds are relatively weak but because there are so many, the total binding effect is strong and stable. The helix is flexible and elastic.
这有一个像弹簧一样的规则盘绕结构，R基团指向螺旋体的外部。氢（H）键相对较弱，但由于数量众多，总的结合效果很强且稳定。螺旋体是灵活和有弹性的。
This is composed of 'side by side' chains connected by H bonds. All the peptide linkages are involved in inter-chain H bonding so the structure is very stable.
这是由H键连接的 "并排 "链组成。所有的肽链都参与了链间H键的连接，所以结构非常稳定。
This is the overall 3-D structure of the protein.
The shape of the protein is held together by H bonds between some of the R groups (side chains) and ionic bonds between positively and negatively charged side chains. These are weak interactions, but together they help give the protein a stable shape. The protein may be reinforced by strong covalent bonds called disulphide bridges which form between two amino acids with sulphur groups on their side chains.
These interactions may be electrostatic attractions between charged groups e.g. NH3 and O- or van der Waal's forces.
这是蛋白质的整体3-D结构。
蛋白质的形状是由一些R基（侧链）之间的H键和带正负电荷的侧链之间的离子键固定在一起。这些都是弱的相互作用，但它们共同帮助赋予蛋白质稳定的形状。蛋白质可能被称为二硫桥的强共价键加强，二硫桥在两个侧链上有硫基的氨基酸之间形成。
这些相互作用可能是带电基团之间的静电吸引，如NH3 和O-或范德瓦尔力。
Fibrous proteins are made of long molecules arranged to form fibres (e.g. in keratin). Several helices may be wound around each other to form very strong fibres. Collagen is another fibrous protein, which has a greater tensile strength than steel because it consists of three polypeptide chains coiled round each other in a triple helix. We are largely held together by collagen as it is found in bones, cartilage, tendons and ligaments.
Globular proteins are made of chains folded into a compact structure. One of the most important classes are the enzymes. Although these folds are less regular than in a helix, they are highly specific and a particular protein will always be folded in the same way. If the structure is disrupted, the protein ceases to function properly and is said to be denatured. An example is insulin, a hormone produced by the pancreas and involved in blood sugar regulation.
A globular protein based mostly on an α-helix is haemoglobin.
A globular protein based mostly on a β-pleated sheet is the immunoglobulin antibody molecule.
纤维蛋白是由长分子排列形成纤维（如角蛋白）。几个螺旋体可以相互缠绕，形成非常坚固的纤维。胶原蛋白是另一种纤维蛋白，它的抗拉强度比钢铁大，因为它是由三条多肽链以三螺旋的方式相互缠绕而成。我们在很大程度上是由胶原蛋白支撑的，因为它存在于骨骼、软骨、肌腱和韧带中。
球状蛋白是由链状物折叠成一个紧凑的结构。其中最重要的一类是酶。尽管这些折叠不如螺旋结构那么有规律，但它们具有高度的特异性，一种特定的蛋白质总是以同样的方式折叠的。如果结构被破坏，蛋白质就会停止正常功能，被称为变性。一个例子是胰岛素，一种由胰腺产生的、参与血糖调节的激素。
一个主要基于α-螺旋的球状蛋白是血红蛋白。
主要以β-褶皱片为基础的球状蛋白是免疫球蛋白抗体分子。
If a protein is made up of several polypeptide chains, the way they are arranged is called the quaternary structure. Again, each protein formed has a precise and specific shape (e.g. haemoglobin)
如果一个蛋白质是由几个多肽链组成的，它们的排列方式被称为四级结构。同样，形成的每个蛋白质都有一个精确而具体的形状（如血红蛋白）。
Prosthetic groups 修复基团The majority of proteins are assisted in their functions by a prosthetic group. This may a simple metal ion such as zinc in the enzyme carboxypeptidase, or it may be a complex organic molecule, such as the haem group in haemoglobin.
大多数蛋白质在其功能中都有一个修复基团的帮助。这可能是一个简单的金属离子，如羧肽酶中的锌，也可能是一个复杂的有机分子，如血红蛋白中的血族。
