The role of the gluten in an acid environment When you make sourdough bread, you usually want more sourdough if you are using a flour with a low percentage of gluten ( minor strength ) and less sourdough if your flour has a good strength .

Now there is a clear connection between the acidity of the sourdough and the gluten ( or protein ) in order to achieve the perfect balance: what is the actual link ?
The link you are looking for is the balance between structure provided by gluten and structure provided by starch.  When there is a lower percentage of gluten, starch has to remain intact to give the bread structure. So, when using a lower gluten flour to make bread you use more sourdough starter so that you can develop a higher level of acidity. This acidity reduces activity of the enzyme alpha amylase and leaves more of the starch intact.  Not developing significant acidity quickly enough will lead to a gummy dough that will collapse during baking.