XML : .Net Xml Serializer uses private attribute name instead of public one

I've generate a class with xsd.exe and it came out like this (a partial):

  public partial class MyClass{               private SignatureType signatureField;        [System.Xml.Serialization.XmlElementAttribute(Namespace = "http://www.w3.org/2000/09/xmldsig#")]      public SignatureType Signature {          get {              return this.signatureField;          }          set {              this.signatureField = value;          }      }      }    

I'm coding an Asp.Net 5 controller that outputs that object as an XML, the problem is that the seriarizer is using the private property's name instead of the public one ending up like this

  <MyClass>      <signatureField></signatureField>  </MyClass>    

with the Field suffix.

What could be causing this?

thanks